2nd Grade Math Compilation - Free Educational videos for Students in K-12 | Lumos Learning

2nd Grade Math Compilation - Free Educational videos for Students in k-12


2nd Grade Math Compilation - By



Transcript
00:00 wow . We are going to learn so many cool
00:03 things on this home school pop video . All right
00:06 . What's the first thing we should learn ? How
00:09 about perimeter ? All right . Let's show you how
00:14 fun this is . Imagine I'm a race car driver
00:18 , Right ? And don't make fun of my car
00:20 . Okay . This is this is a perfectly good
00:22 car to do a racing , right ? It's very
00:24 fast . It's got the bells has got the whistles
00:27 . It's a great race car . Okay , stop
00:30 laughing at it . Okay , now , imagine this
00:34 is the race car course that I'm driving on ,
00:37 Right ? It's going around an oval . It's going
00:40 around a shape . If I was wondering , how
00:46 far is it around the track ? What's the distance
00:49 around the shape , then ? I would need to
00:52 know the perimeter . The perimeter is the distance around
00:57 a shape . Wait , wait , wait . What
01:01 is the perimeter ? The perimeter of a shape is
01:07 the distance around a shape . And it's easy to
01:13 find . You can find the perimeter of a shape
01:16 by adding all of the sides that will tell you
01:20 what the distance around the shape is . Great .
01:26 Now let's practice finding the perimeter . Look at this
01:29 triangle . What is the perimeter of this triangle ?
01:34 Okay . First we need to know how long all
01:38 of the sides are . Then we can figure out
01:41 the perimeter with this triangle . All three sides are
01:47 the same length . So how long are they ?
01:50 Let's pretend we measured it and each side is 10
01:54 cm . Now , remember to find the perimeter of
02:00 a shape . We need to know the distance around
02:02 the whole shape . So we just add the sides
02:05 together . What's 10 plus 10 plus 10 ? That's
02:10 3 10s . What does that equal ? Yeah ,
02:15 30 . Mhm . Awesome . The perimeter of this
02:20 triangle is 30 centimeters . Remember cm is an abbreviation
02:26 for centimeters 30 centimeters . Is the perimeter of this
02:30 triangle . Okay , let's try this one . What
02:37 is the perimeter of this square ? First we need
02:43 to know how long all the sides of the square
02:46 are . Then we can figure out the perimeter of
02:48 the square . Okay , so this is a square
02:53 . It has four sides and all four sides are
02:57 the same side . Let's pretend we measured it and
03:01 each side is one yard . Remember why D is
03:06 an abbreviation for the distance of a yard ? Each
03:10 side is one yard . Remember the perimeter is the
03:17 distance around a shape . So we'll need to add
03:21 all of these sides up . Okay , what's one
03:25 plus one plus one plus one ? Yeah . Four
03:33 . The perimeter of this square is four yards .
03:38 The perimeter , remember , is the distance around a
03:41 shape . If you were to go around this entire
03:43 square it would be four yards . Okay , this
03:51 is the final one . What is the perimeter of
03:54 this rectangle ? Well , first we need to know
03:59 how long all the sides of the rectangle are ,
04:03 then we can figure out the perimeter . Remember .
04:09 A rectangle has four sides and two of the sides
04:13 are shorter than the other two sides with this rectangle
04:18 . Let's pretend we measured it at one m on
04:21 the short sides and three m on the longer sides
04:28 . Okay , remember to get the perimeter , we
04:30 have to add all of the sides together . So
04:33 we're going to be adding four numbers together again .
04:36 To make it easier , we're going to group the
04:38 smaller numbers together and then put the larger numbers in
04:43 our equation . What's one plus one plus three plus
04:49 three ? Those are all the sides . What's one
04:52 plus one plus three plus three ? Yeah . Yeah
04:59 . Eight . Mhm . That means the perimeter of
05:06 this rectangle is eight m , wow . We told
05:12 you it was gonna be fun . Oh , it's
05:14 such a blast . Finding the perimeter the perimeter is
05:17 so much fun to find . It's like a game
05:22 . Remember you can find the perimeter of a shape
05:26 by adding all of the sides and the perimeter of
05:32 a shape is the distance around a shape I'm so
05:40 proud of you , I'm so proud of . Now
05:43 . You know how to find the perimeter of something
05:45 . The perimeter is the distance around a shape .
05:48 I can find the perimeter of this tablet . Right
05:51 ? All I would need to do is measure each
05:53 side and add them together . And I would find
05:57 the perimeter right now . I I gotta find an
06:00 internet connection . There's no Wifi out here . There's
06:02 no reason to be in the desert . I need
06:04 water . There's not . This doesn't make any sense
06:07 . Okay , so I'm gonna go you go ahead
06:11 and find perimeter . Enjoy the perimeter is a distance
06:14 around the shape . Go have fun . Thanks for
06:17 watching . Yeah , Yeah . We are so happy
06:26 to have you with us . I mean you are
06:28 so awesome . You really are . Oh , you
06:31 like my poster Mr Whiskers poster . You know ,
06:35 it's pretty cool . Pretty cool . You know ,
06:38 it's a pretty cool poster . Pretty cool cat too
06:41 . I wonder what he would like to learn about
06:43 next if he would learn from one of our videos
06:46 , what would he like to learn next ? How
06:49 about let's learn about fractions ? Fractions are so awesome
06:58 and so much fun . Yeah , many of you
07:02 think so too . A couple of weeks ago we
07:04 set up a poll on our channel and many of
07:07 you voted for fractions as our next math video .
07:11 That's really awesome . Thanks everyone for voting . And
07:14 don't worry , we'll make the other two videos to
07:16 later on . But this is all about fractions .
07:20 All right , well let's start here . What is
07:25 a fraction when we say the word fraction , What
07:27 do we mean ? What is a fraction ? Well
07:33 , a fraction is something that shows parts of a
07:35 whole , let's say there's this lady named Cindy .
07:42 Cindy has a pizza , which is great . She
07:47 loves pizza . So yeah , me pizza . But
07:53 then her friend chomsky arrives . You remember chomsky chomsky
07:57 likes pizza too and he's a little bit hungry .
08:00 So maybe Cindy isn't going to eat the whole pizza
08:03 now , maybe they're gonna split it . What do
08:06 you think ? So they split the pizza in half
08:11 . Each of them get one half of the pizza
08:14 that neat . Then everyone has pizza . Each of
08:18 them have one half of the pizza . They split
08:21 it right down the middle . Now remember a fraction
08:27 is something that shows parts of a whole . So
08:32 here is what the fraction looks like a one a
08:36 line and the two that is the fraction . One
08:40 half each of them . Cindy and chomsky get one
08:44 half of the pizza . So this is one half
08:51 . It's a very important fraction because we use it
08:55 all the time . Now . You might be wondering
08:57 what do the numbers mean ? And how does it
09:00 show one half ? Well , the bottom number shows
09:06 the total number of parts . The top number shows
09:13 how many parts we are talking about . Pretty simple
09:17 . Let's go back to our example . There are
09:23 a total of two parts to the pizza , so
09:26 there's a two on the bottom and Cindy just gets
09:30 one part , that's the part we're talking about .
09:33 So Cindy gets just one half of the pizza ,
09:37 she doesn't get the whole thing , she gets just
09:40 one part , she gets one half . The bottom
09:45 number of a fraction is called the denominator . The
09:49 denominator is the total number of parts . The top
09:57 number is called the numerator . The numerator tells us
10:00 how many parts we are talking about in this case
10:04 Cindy is having one part of the pizza , the
10:08 other part of course is going to chomsky , let's
10:13 try this , let's say there's another pizza and this
10:16 pizza has four parts . The number four is the
10:21 denominator because there are four pieces of pizza , four
10:27 parts let's say kelly shows up and wants to have
10:34 one part of the pizza , one piece of the
10:38 pizza , the numerator or the top number of the
10:43 fraction is the number one because kelly is having one
10:49 part or one piece of the pizza , kelly is
10:54 having 1/4 of the pizza . Pretty simple , pretty
10:58 fun , fractions are awesome . Mm Now we're going
11:04 to need your help help us figure out what fraction
11:10 is it ? What fraction is it ? Wow ,
11:15 we're gonna have a great time . Let's say we
11:20 have a group of five sports balls . One is
11:24 a basketball , the other four are soccer balls .
11:30 Let's figure out what fraction of the balls are basketballs
11:36 . What fraction of the balls are basketballs . So
11:45 we know a fraction has a line in the middle
11:47 and the top number is the numerator and the bottom
11:50 number is the denominator . The denominator shows us the
11:55 total number of parts or units . How many sports
11:59 balls are there ? Yeah . 5 . 5 is
12:07 the denominator . Good job . Now remember we're asking
12:12 for the fraction of sports balls that are basketball's .
12:17 So how many basketballs are there ? Yeah , just
12:24 one . The number one is the numerator . So
12:29 1/5 of the sports balls are basketball's 1/5 . Great
12:36 job . Let's try this final example . Let's say
12:41 there are five pets . 5 pets two of them
12:46 are dogs and three of them are cats . What
12:54 fraction of the pets are cats ? Huh ? That's
12:57 a good question . What fraction of the pets are
13:01 cats ? Remember ? Here's what a fraction looks like
13:06 . It's got a line in the middle with the
13:08 top number being the numerator . And the bottom number
13:11 is the denominator . So the total number of pets
13:19 is five . What number is the denominator ? What
13:22 number goes on ? The bottom ? Yeah . 5
13:28 . 5 is the denominator . It tells us the
13:31 total number of bets . Remember we're asking for the
13:38 fraction of the pets that are cats ? How many
13:42 cats are there ? Yeah . three . So what's
13:47 the numerator ? Yeah . 33 is the numerator .
13:54 3/5 of the pets are cats , wow , that
13:59 was so cool . But none of those catcher is
14:06 special to me . As you . Mr whiskers .
14:09 Not even a fraction of my heart belongs to my
14:12 whole heart . I love you . Mr whiskers .
14:15 I do I do . A fraction is something that
14:21 shows parts of a whole . The top number of
14:28 a fraction is the numerator . How many parts we
14:31 are talking about ? And the bottom number of a
14:34 fraction is the denominator . The total number of parts
14:41 . Oh wow . Look it's the homophone cow homophone
14:44 cow hama phone cattle . You're just walking . You're
14:49 just just gonna ignore me . I see how it
14:52 is . Okay so you're upset that we haven't included
14:55 you in other videos . What do you call this
14:57 ? You know you're in a compilation video . That's
15:00 cool too . All right I need to talk to
15:03 the homophone cow . But in the meantime let's learn
15:08 about multiplication . You're gonna learn how to multiply and
15:12 if that sounds really scarier , if that sounds like
15:15 a difficult thing , it's just because you don't know
15:18 how to do it yet . Once you learn the
15:20 game , once you learn the process , it's fun
15:23 . It's awesome . You see , multiplying is like
15:28 being a detective , you're cracking a code , which
15:31 is so cool , you're solving mysteries like legit mysteries
15:35 . Like I'm I'm in an office building right now
15:38 . There's a cake behind me . For some reason
15:40 , I'm looking out right now , are you guys
15:42 ? And I see that you're like , whoa ,
15:43 we're gonna multiply thanks . And once you learn it's
15:47 just a game , so buckle in for the fun
15:50 and the learning , let's say you have two bikes
15:55 and for some reason they look the exact same and
15:59 somebody wants to give you an air pump . They
16:04 ask a simple question . How many tires do you
16:07 have to take care of you to figure that out
16:11 ? We're gonna use multiplication . We're gonna play the
16:14 game . It's gonna be awesome . Okay , So
16:19 here is how multiplication works . So we put the
16:24 number that's in each group and then we put this
16:28 X . Which means times and then the number of
16:31 groups . So that tells us how many times that
16:34 number is going to show up , and then we
16:36 add them all together . And you've got your answer
16:39 . Isn't that cool ? Mhm . And just a
16:43 side note to work , there has to be the
16:45 same number in each group . Big people . Now
16:51 remember , we're trying to figure out how many tires
16:53 you have to take care of if you have two
16:56 bicycles . All right now , we have the wheels
17:00 under each bike . Each bike has two wheels 12
17:09 So we write down A . To each bike has
17:13 two wheels . Remember the first number we write down
17:20 with multiplication is the number in each group . Then
17:27 we write an X . This X means times two
17:32 times . It's the symbol of multiplication . Right ?
17:38 All right . The second number we Right . Are
17:40 the number of groups . You can see them here
17:42 . How many groups do we have of two ?
17:46 How many ? Yeah , too . So it reads
17:52 two times to you to figure this out . We
17:58 are going to skip . Count by two , 24
18:05 That means two times two equals four . If you
18:12 have two bikes , that means you have four wheels
18:15 . 22 times is four . Remember , this is
18:22 how multiplication works . The number in each group times
18:28 the number of groups equals your answer . The of
18:34 course to work . There has to be the same
18:37 number in each group . All right , let's take
18:41 this to the next level . Let's say someone has
18:43 four bikes and here are their wheels . You know
18:52 how to do this ? Now , each bike has
18:55 two wheels . To the first number we write down
18:57 is the number two . That's the number in each
19:00 group . We're gonna put the time symbol there and
19:06 count the number of groups . 1234 So , it's
19:10 two times four . This is so much fun .
19:15 This is multiplication . Now , let's skip . Count
19:22 to get the answer . 2468 Eight is our answer
19:31 . There are eight wheels . Two times four equals
19:34 eight . This is how multiplication works . Mhm .
19:42 We put the number in each group times the number
19:45 of groups . And we get our answer . You're
19:50 getting the hang of it . All right , let's
19:52 try this one . Mhm . Let's say you buy
19:57 three packs of trading cards . Let's say each pack
20:03 had five cards in it . Huh ? That's pretty
20:06 good amount . So , three packs of five cards
20:11 sugar . How many cards did you get in total
20:15 ? It's a really great question . Sounds like we're
20:19 gonna need to multiply . So each group has five
20:26 . So that's the first thing . We write down
20:28 the number in each group . That's five . Put
20:32 the multiplication sign which is the X . Which means
20:35 times five times how many groups are there ? 123
20:45 So the second number is 35 times three . What's
20:51 five times three ? We're gonna skip count to find
20:55 out . 5 , 10 , 15 . Five times
21:04 three equals 15 . You have 15 trading cards .
21:12 All right , this is how it works . You
21:16 take the number in each group times the number of
21:19 groups . And you get your answer . Now here
21:26 are some multiplication tricks that are going to be really
21:29 sneaky ways that you can figure out multiplication problems really
21:34 , really quickly . Here's the trick . If you
21:37 multiply any number by zero , you always get zero
21:42 Always , you always get zero . Here's an example
21:49 , five times zero equals zero . When you have
21:53 zero groups of five , that means you have zero
21:56 , there are none . Whenever you multiply any number
21:59 by zero , you always get 0 , 100 times
22:03 zero equals zero . My friend . Even if zero
22:11 is the first number in the equation , you still
22:13 always get zero . When you multiply by any number
22:17 . For example , zero times 11 equals zero and
22:25 zero times 1000 equal zero . If you multiply any
22:30 number by zero , you always get zero . Oh
22:35 , this has been so much fun . Here is
22:37 the next trick . If you multiply any number by
22:45 one , it stays the same . Look at these
22:49 seven times one equals 7 , 100 times one equals
22:53 130 . 3 times one equals 33 mm . If
23:01 you flip them , the answer stays the same one
23:04 times seven equals 71 times 100 equals 101 times 33
23:09 equals 33 . Honestly , the order of the multiplied
23:13 numbers does not change the answer . Yeah . If
23:20 you were to flip the number of groups and the
23:22 number of each group , you would still get the
23:25 same answer . So we still recommend this way .
23:30 So simple . The number in each group times the
23:33 number of groups to get your answer . So the
23:40 two tricks have been , If you multiply any number
23:43 by zero , you always get zero and if you
23:50 multiply any number by one , it stays the same
23:54 . The final multiplication trick is to use multiplication tables
24:04 . They come in all shapes and sizes , but
24:07 they are all helpful , especially as you're first learning
24:10 how to multiply . Here are some examples of multiplication
24:14 tables . There's a table for all of the numbers
24:17 from 1 to 10 mm . Some kids memorize tables
24:25 like these so that they'll know right off the bat
24:28 in a moment . What an answer could be for
24:31 certain multiplication problems . This is how multiplication works .
24:36 The number in each group times the number of groups
24:40 gives us our answer . Oh , this is such
24:47 a heavy cart . Oh my goodness . It's hard
24:52 work . You know , a lot of times learning
24:54 can be hard work too . But we hope that
24:57 these videos are really helpful . Make learning fun .
25:00 So that learning is hard like pushing this cart .
25:03 Oh my goodness ! All right , what's the next
25:06 thing we should learn about ? Let's learn about three
25:12 dimensional shapes . This is gonna be awesome . Love
25:15 the three d shapes . A lot of people know
25:17 the two d shapes . You might not know the
25:19 three D shapes . You're in the right place .
25:22 Before we get started . We just dance here real
25:24 quick . This is really cool music . I really
25:27 like this . You know , I like to dance
25:29 . You know , some people they're not dancers .
25:30 You know , I dance , I dabble and dancing
25:34 , you know ? All right , that's enough .
25:37 Can somebody turn that music off ? Seriously ? I
25:40 can't teach like this . I can't teach with this
25:42 music going on . You know , I feel like
25:44 I'm in a candy shop . Let's just start the
25:46 music off , please . Thanks . So here they
25:51 are our old friends , the two D shapes .
25:54 You're familiar with these . You know , you're familiar
25:56 with the circle , the oval , the triangle ,
26:00 the pentagon , the trapezoid , the hex a gone
26:05 , the square , the rectangle , the parallelogram in
26:08 the octagon . These are all our our shapes ,
26:12 r two D shapes , you know , But these
26:14 are old family friends of ours . We don't want
26:17 to just Forget about these before we look at 3D
26:20 shapes . It's really important for us to look at
26:23 these shapes again because these are old friends . So
26:26 we're gonna look at each one of these one by
26:28 one . Just to make sure you know who they
26:31 are . Before we learn all these new shapes .
26:35 This first shape doesn't even need an introduction . It's
26:38 the circle , the circle , that round figure .
26:42 It's awesome . We love this shape . It's one
26:45 of the first ones we ever learn the circle .
26:50 This next shape is one of the stretchy shapes .
26:53 The oval , it's like a circle got stretched out
26:56 . Its elongated . It's a tremendous shape . The
27:01 oval , mm . Mhm . Here's another familiar shape
27:07 . The triangle . Three sides . We love the
27:12 triangle . The triangle is great , the three sighted
27:15 friend . Three sides . A triangle . Wait ,
27:21 I keep saying we love the shapes . I mean
27:23 we like the shapes . But do you love the
27:26 shapes ? Do I love the shapes ? I mean
27:29 I don't know . I need to take it easy
27:32 here , huh ? All right , let's keep going
27:35 . Mhm . Ah The square of four sides all
27:39 equal . You know the square is good . The
27:42 squares a good shape . You know sometimes you just
27:45 need a square . Sometimes you just need a square
27:51 . Here's the rectangle . The rectangle is longer than
27:55 the square because not all four sides are equal .
28:00 The rectangle . I know I'm we're in the middle
28:06 of something here , but I have to share this
28:07 . Okay , so what do you call a hamster
28:11 with the top hat ? Abraham stir Lincoln . I
28:18 digress the trapezoid , a cool shape with two of
28:24 the sides being parallel to each other . In the
28:27 parallelogram . Another four sided shape . Both pairs of
28:31 sides are parallel to each other and finally the pentagon
28:37 with five sides . The hex a gone with six
28:40 sides and the octagon with eight sides . What awesome
28:45 shapes . So let's go ahead and do a quick
28:52 to D shaped quiz . I need your help .
28:55 I want to see if you really learn these ,
28:57 if you really know these before we get into the
28:59 three D . Shape . So help me out here
29:01 we're gonna have an awesome time . Wait what ?
29:06 What ? It's not my birthday . Oh well what
29:11 type of shape is on the top ? Yeah .
29:17 Yeah . A circle . What type of shape is
29:21 in the middle ? A square awesome . Okay now
29:29 what shape is on the bottom ? Of course A
29:36 triangle awesome job . Now we've got more , this
29:42 is a little trickier . Which shape is in the
29:44 middle ? This yeah a trapezoid . Which shape is
29:53 on the right , The pentagon . Good job .
30:00 And which shape is on the left . Yeah the
30:08 square . Now try these . Which shape is on
30:15 the bottom ? Yeah . The oval . Which shape
30:22 is on the top . Yeah . Yeah . The
30:29 parallelogram which shape is in the middle ? Yeah .
30:36 All right . The rectangle . Great job . All
30:42 right . The last one . Which shape is on
30:46 the left ? Yeah . The hexagon . Which shape
30:55 is on the right , Great . The octagon .
31:03 And which shape is in the middle ? Yeah ,
31:08 phenomenal . The pentagon . All right . We're ready
31:14 to learn the 3D shapes . We're going to learn
31:16 how to identify the three dimensional shapes . If you
31:21 struggle through the quiz you might want to watch the
31:23 first part of the video again . Otherwise let's get
31:26 started . So as we're starting out it's important to
31:31 remember what makes a 3D shape a 3D shape .
31:35 There's an old rhyme that says three D shapes are
31:39 fat , not flat . And you can see that
31:41 with the sphere which is a three D . Shape
31:44 we're about to learn and the circle the circle is
31:48 flat but the sphere is three D . It's three
31:52 Dimensional . All the shapes are like that . So
31:55 let's learn all these three D shapes . So the
31:59 first three D shape we're going to learn is the
32:02 sphere . The one that we just mentioned . The
32:04 sphere is the three D version of the circle .
32:09 It's perfectly round . There are spheres all around us
32:16 . One of the spheres we see all the time
32:18 . Our balls like this soccer ball , a soccer
32:22 ball is a sphere . It's perfectly round . It's
32:25 a three D circle . It's a sphere . You
32:28 know this fear ? Yes , it's the earth ,
32:31 it's where we live . Our planet is a sphere
32:35 . How cool is that ? Our own planet is
32:38 a sphere perfectly round . It's a sphere in this
32:44 picture we have two spheres . Can you spot them
32:48 ? Yeah , the two spheres are the two bullying
32:52 balls . Perfect round spheres , spheres are all around
32:57 us . Here we have a group of three spheres
33:02 and you can count them right now . 123 spheres
33:07 . All together the shape of a ball . A
33:09 sphere perfectly round . Well there you have it .
33:15 The sphere . What a cool three D shape to
33:18 start with . Its round there . Examples all around
33:22 us and it's just so cool and you know what
33:24 ? The three D shapes are going to get even
33:27 better . Our second three D shape is the cone
33:33 . The cone is a really cool shape with a
33:35 circle as the base or the bottom . And it
33:39 all comes up to one point called a vertex .
33:43 Here's an example of a cone . I think we
33:46 all love the ice cream cone . If it doesn't
33:49 have any ice cream inside and you flipped it upside
33:51 down , you'd be able to see the circle base
33:53 and it all comes up to one point called the
33:56 vertex here are two cones , a red cone and
34:02 a blue cone . And you can see both cones
34:05 have that circle basin all comes up to a vertex
34:10 . What wonderful cones have you seen these before ?
34:15 Their traffic cones here are many cones . I didn't
34:20 count all of them but there's a lot and they're
34:23 wonderful wonderful cones . Yeah so that's our second three
34:29 D shape . The kona wonderful cone with the great
34:33 circle base . It all comes up to one point
34:36 called the vertex . How awesome is that ? Our
34:42 third three D shape is the pyramid . I love
34:44 the pyramid . The pyramid is great . It comes
34:47 up to one point just like the cone except the
34:49 base is a square and the sides instead of being
34:52 smooth . They are triangles . Okay , like these
34:58 are awesome . These are so cool . The pyramids
35:02 of Egypt , you see that they have the triangle
35:05 sides and the bottoms of these pyramids are square .
35:09 They're awesome . Examples of the pyramid . This is
35:12 a pretty cool pyramid . It's a decoration that you
35:15 plug into the wall , but it's a great example
35:18 of what a pyramid looks like the bottom of the
35:20 bases square . And there's the triangles on the sides
35:24 . How cool is this ? Here's another pyramid and
35:29 it's made of glass . There are so many decorations
35:33 and things around . Maybe even your house that are
35:36 shaped like a pyramid because pyramids look so cool .
35:39 People love putting them everywhere . There you go .
35:42 I mean you know the pyramid , it's a good
35:44 shape . You know , you see a lot of
35:45 them around , they've got the square bottom or base
35:49 and the triangles on the sides and all goes up
35:52 to a vertex . It's a classic shape . It's
35:55 pretty awesome . Our 43D shape is the cylinder .
36:00 Now , a cylinder is easy to spot because it's
36:03 got a circle on the top and a circle on
36:05 the bottom and it's smooth all around here , we
36:13 have a can of soup and it's a cylinder has
36:16 a circle on the top , a circle on the
36:19 bottom and it's smooth all around all cans . And
36:23 most jars are cylinders . Here we have three cylinders
36:28 . Their candles . And can I tell you a
36:30 secret ? Most candles are cylinders to right , Oh
36:36 my God , this this is just too crazy and
36:39 too awesome . Yeah , Here are two more cylinders
36:44 . Are you kidding me ? Are you kidding me
36:46 ? Even batteries are cylinders , cylinders are seriously everywhere
36:50 . A circle on the top , a circle on
36:53 the bottom and smooth all around . I mean really
36:57 the cylinder is everywhere . I mean you know the
37:00 circle on the top circle on the bottom smooth all
37:03 around . I cylinder . Like what in the world
37:06 do you have to be everywhere ? Okay , the
37:12 next three D shape is the cube . The cube
37:15 is the three D version of the square . It
37:18 has six sides or faces that are all squares .
37:26 Here we have two dice dice are in the shape
37:30 of a cube . So these two dice or two
37:34 cubes , they have six sides or faces that are
37:37 all squares here we have many cubes . These are
37:44 cubes that are made out of wood . Each of
37:47 them have six sides or faces that are all squares
37:56 . Here are seven cubes of ice . Have you
37:59 ever had a warm drink and you need to put
38:01 ice in it ? It's awesome because it has this
38:03 great shape , the shape of a cube , six
38:08 sides or faces . All squares . I mean there
38:11 you go . The cube right ? The three D
38:15 version of a square and it's got squares all along
38:19 The sides right there . six sides or faces all
38:22 squares . And I don't know . I think it's
38:24 pretty cool shape . Our final three D shape is
38:30 the rectangular prism . The rectangular prism is the three
38:34 D version of the rectangle . It has six sides
38:38 or faces that are all ready . Okay . An
38:41 awesome example of the rectangular prism are bricks and here
38:45 we have four bricks which are four rectangular prisms .
38:50 The three D version of the Rectangle . You may
38:57 have seen this in your classroom or in your home
39:00 . It's a clean Xbox . And the clean Xbox
39:03 is a great example of the rectangular prism . It's
39:06 got six sides or faces that are all rectangles .
39:10 Okay , so the secret is most boxes are rectangular
39:14 prism . So here's another rectangular prism and it's a
39:18 box and it's a shorter box but it still has
39:20 rectangles all around . And it's rectangular prism . What
39:28 else can we say ? It's a cool shape .
39:30 The rectangular prism is the three D version of the
39:32 rectangle . It has six sides or faces that are
39:35 all rectangles . And it's just a neat shape to
39:39 have around I think I mean you know . Okay
39:43 so let's review pyramid cylinders . Okay . Mhm sphere
40:18 . Mhm cylinder cones . Yeah . Yeah . Pyramid
40:41 , rectangular prism . Yeah . Mhm spheres . Okay
40:53 , let's do some more On the top . Here
40:59 we have cubes . We can tell that because it's
41:03 a 3D square . It has six sides or faces
41:07 . Each of them are squares . Is pretty cool
41:10 . Do you remember what shape these bricks are ?
41:14 Yeah , a rectangular prism . They are rectangular prisms
41:18 there , the 3D versions of the rectangle , mm
41:26 at the top . We have a cone , a
41:30 cone . It's got a circle base on the bottom
41:34 and all comes up to one point called a vertex
41:39 . Do you remember the shape here on the bottom
41:42 ? These are three cylinders . They have a circle
41:46 on the top and a circle on the bottom and
41:49 it's smooth all around . You're doing such an awesome
41:57 job . Seriously . So cool . So what's this
42:00 top shape do you remember ? Yeah , it's a
42:03 pyramid . A pyramid . A pyramid has a square
42:07 base . It comes up to one vertex or one
42:10 point and has triangles as the sides . All right
42:19 . Do you remember this last shape here on the
42:21 bottom ? Yes , it's the sphere . The sphere
42:25 , which is the three D . Circle . And
42:27 we started with it and we're ending with it and
42:30 it's so awesome . Hey ? Well , okay ,
42:35 first of all elephants don't drive . Okay , elephants
42:39 can't get a driver's license and he's driving on the
42:42 grass . He's driving on the grass . You're gonna
42:45 row in the lawn . Okay , let's go it
42:47 on it . All right , This is out of
42:50 hand . Okay , elephant , I don't want to
42:53 tell you what you can do what you can't do
42:55 what you can't drive . All right . Oh my
42:58 goodness . All right . Next we are going to
43:01 learn about roman numerals , which is a different way
43:05 to write numbers . And it was used a long
43:08 time ago in ancient Rome . And it's been used
43:11 since then . And you can think of it almost
43:14 as a secret code way of writing the numbers .
43:17 It's pretty simple to learn . And we're going to
43:19 go through that . The first roman numeral we're gonna
43:24 learn is the roman numeral . I and I is
43:29 one I equals one . So if you see an
43:34 eye with the roman numeral , it's one the letter
43:37 V . Is the roman numeral that means five .
43:41 And the letter X . Is the roman numeral ,
43:45 that means 10 . So when you think one it's
43:50 an eye , you think five it's a V .
43:53 If you think 10 it's an X . So that's
43:59 it just those three . I it almost looks like
44:04 a one . That's how you can remember that .
44:06 I is a one I . Is the roman numeral
44:09 for one . A . V . Is in the
44:12 number five . When you spell it out , the
44:14 number five you see that right there . It has
44:16 a V . In it . So when you think
44:18 of V . You know oh you know what there's
44:21 a V . In the spelled out number five .
44:26 So the has to be five now . 10 is
44:29 exit . We can't think of anything that could remind
44:33 us of that . So there is no memorization thing
44:36 just when you see the exits 10 and that's just
44:39 what we're going to have to do . Okay one
44:43 last time here , I just want to make sure
44:45 you get it . There's only three . I is
44:47 the roman numeral for one , the is the roman
44:51 numeral for five and X is the roman numeral for
44:55 10 . And you've got to understand that so that
44:57 we can start playing kind of a game of putting
45:00 them together and making numbers Other than just 15 and
45:06 10 . So let's get started . So let's practice
45:11 putting these Roman numerals together . What number do you
45:15 think ? This is ? Two U . C .
45:20 Two eyes two and i is one . So the
45:25 answer is to two eyes is the number 21 What
45:35 about this one ? You what number do you think
45:38 ? This is ? Why there are three eyes ?
45:43 Yeah it's the number three . Let's try this one
45:52 . What number do you think this is ? We
45:57 see two X . Is an X equals 10 .
46:02 So 10 plus 10 equals 20 . Great job .
46:08 This is the number 20 . Whoa . This one
46:16 is so cool . Okay . X . And V
46:20 . What number do you think ? This is the
46:26 X . Is a 10 ? The V . Is
46:30 what number five ? Awesome . So what is 10
46:36 plus five ? 15 . Whoa . Thanks so much
46:42 for helping out now that we've looked at how to
46:47 put some of these together . I want to tell
46:49 you about two special numerals that are a little bit
46:52 different . And so you're gonna have to just remember
46:55 these on their own . The first is the number
46:58 four and the number four is represented with an I
47:02 . And V . And eyes before the V .
47:05 Because four is one less than five which is V
47:09 . So remember with four its I . V .
47:14 With nine . It's similar except with the X .
47:17 Nine is I . X . X . Is 10
47:20 . And eyes just before it . So nine is
47:24 i . x . Okay . That was really cool
47:29 . Thanks for hanging out and learning those with me
47:31 . But we're not done . We want to go
47:33 through all the numbers up to 30 just using the
47:38 numerals and I want to see how much you've really
47:41 learned . So if you'll do me a favor as
47:43 the numerals go up , I want you to say
47:46 the numbers along with me and we can practice together
47:50 . Sound good . Alright , let's get started .
47:54 Mhm . One two three four five . Sex seven
48:11 eight nine , mm 10 11 , Yeah . 12
48:21 13 , 14 , 15 , 16 , 17 ,
48:33 18 , 19 , 20 21 22 23 24 ,
48:45 25 26 , 27 28 29 and 30 . Mhm
48:56 . Well there you have a new way to write
48:59 numbers , wow , mom , you're doing such a
49:03 great job in your race . I had no idea
49:06 you were an athlete . Okay . I mean with
49:08 all that cloth wrapped around , you're doing great .
49:11 You're doing a great job . Just like these kids
49:13 are doing a great job of learning . In fact
49:16 , how about this ? The next thing we're gonna
49:18 learn about is division . Division is such an awesome
49:25 thing to be able to do . And you're going
49:27 to have it all figured out . You're gonna learn
49:29 how to divide . In this video . We're gonna
49:33 start off with a story . There's this kid named
49:35 Ethan and Ethan loves carrots . He loves carrots so
49:40 much he loves to stack on him . He loves
49:43 when he gets to eat them . They're crunchy .
49:45 They're tasty . Yeah , carrots are awesome . In
49:50 fact , I'm literally eating a carrot right now .
49:53 As I'm speaking , carrots are great for your skin
49:56 . Carrots are great for your eyes , they're amazing
49:58 . You're a great snack . And Ethan loves them
50:03 . Well Ethan has two friends over Kevin and Chloe
50:07 and they start to get hungry . Mm Of course
50:12 they all love carrots because carrots are like the perfect
50:16 snack . Now in Ethan is house , there are
50:19 only three carrots . They're just three carats . We
50:24 are going to have to divide the three carats amongst
50:28 the three kids . So let's figure this out .
50:31 How many carats does each kid get ? Do you
50:35 know ? Mm Uh huh . Each kid gets one
50:41 carat pretty simple . Right ? Three carats . Three
50:45 kids . Each kid gets one carrot . Mm Hey
50:50 , did you know we just did division . Uh
50:53 huh . We just did division . Mm Division is
50:57 pretty simple . You see division is splitting a number
51:01 up by any given number . That's it . Just
51:04 splitting a number up . Let's look at our story
51:09 again , There were three carrots . And we divided
51:12 those three carats by three because there are three people
51:17 , Right ? The three kids that love carrots .
51:20 And the answer of how many carats each kid gets
51:24 Is 1 , 3 divided by three equals 1 notice
51:33 . Right ? Here is the division sign . This
51:36 is what it looks like . When you see that
51:38 sign , you could just say divided by So this
51:41 reads three divided by three equals one . Let's try
51:47 another example of division . Let's say there are eight
51:51 presents , eight presents . And there are four women
51:55 . And we want each of the women to get
51:57 the same amount of presence as the other women .
52:00 Because we want it to be fair notice the division
52:06 sign we are going to divide or split up 8x4
52:12 . Remember to divide us to split up . Let's
52:16 split these presents up into four equal groups . 1234
52:23 All right . How many presents does each woman get
52:28 ? Uh huh . To each woman gets to presents
52:33 . Mm . Yeah . Isn't that cool ? Division
52:37 is so much fun . And it's so easy .
52:41 Remember , division is splitting a number up by any
52:45 given number . That's it . Mhm . All right
52:52 . Now it's time for division facts . We're going
52:55 to learn some pretty interesting facts about division . And
53:00 you're gonna be like , oh my goodness . Like
53:03 secrets . This is super cool . Okay , so
53:06 just look around . All right , make sure .
53:09 Right , who's clear are you ? It's time for
53:11 division facts . The first fact is this You can
53:21 never divide by zero . It's true . You can
53:24 never divide by zero . Even if you're a rule
53:27 breaker and you're like I'm gonna do whatever I want
53:30 . You still can never divide by zero . In
53:33 fact , if a teacher ever gives you a test
53:36 and you see a problem where you have to divide
53:39 a number by zero , just right on the test
53:42 undefined because that's exactly what that answer would be undefined
53:47 . It's impossible . Kind of like Mr Whiskers Math
53:52 skills does Mr Whiskers do math in his head all
53:56 day long . Who knows ? His Math skills are
53:59 undefined ? We just don't know . It's impossible to
54:02 know . You know Mr Whiskers might know how to
54:04 do division . Who knows ? Undefined ? You can't
54:08 divide by zero . You can never divide by zero
54:16 . If you ever see any division problem dividing by
54:20 zero , just right undefined . It's impossible . It's
54:24 impossible . So just write undefined . The second fact
54:29 is this , you can write the division sign three
54:35 ways . Uh huh . Not just with that traditional
54:39 division sign , you can write it like the division
54:42 sign . Or you can write a division problem with
54:45 the slash or with a horizontal line For example .
54:53 Look at this 12 divided by three equals four .
54:56 That's the original division sign . The one that you
54:59 might see more regularly . Yeah . Yeah but here
55:05 is the same equation written in a different way .
55:08 12 divided by three equals four . It's still a
55:12 division sign but it's a slash . It means the
55:15 same thing as the original division sign . Remember the
55:21 division sign can also be a horizontal line . 12
55:25 divided by three equals four . That looks like a
55:28 fraction , doesn't it ? The line in a fraction
55:31 means divided by . These are the three ways that
55:39 you can write the division sign . Pretty interesting .
55:44 Okay . Alright . The final fact is this .
55:49 Yeah . Okay . This is so awesome . You
55:53 can flip the number of groups and the number in
55:56 each group and the division problem stays true . For
56:01 example 10 divided by two equals 5 . And you
56:05 can flip the two and the five and it stays
56:08 true . Yeah , that means 10 divided by five
56:15 equals two . Isn't that interesting ? 10 divided by
56:18 two equals five and 10 divided by five equals two
56:23 . You can flip the number of groups and the
56:25 number in each group and it still stays true .
56:29 Or look at this 18 divided by six equals three
56:33 . Remember we can flip the number of groups and
56:37 the number in each group and it still stays true
56:40 . So we could switch the six and the three
56:43 and it stays true . Okay , so 18 divided
56:48 by three equals six . The six and the three
56:51 can be flipped . So 18 divided by six equals
56:55 three and 18 divided by three equals six . Pretty
56:59 nifty . Those were some cool facts . You know
57:03 , division is a great time . Division is splitting
57:05 a number up by any given number . It's a
57:09 lot of fun . And we hope you learned a
57:11 whole lot in this video . Wow . You completed
57:16 the video . That is so impressive . Well ,
57:19 you might notice there's a circle right here on this
57:22 video page that you can click to subscribe to our
57:25 channel or you can click this rectangle to go to
57:28 another one of our videos . But keep learning .
57:32 Learning is so cool .
Summarizer

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2nd Grade math is fun with these learning videos! Each lesson can help students with word problems, math games or help prepare for a test! Great for a review of 2nd grade or for an introduction!

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2nd Grade Math Compilation is a free educational video by .

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