Using Parenthesis in Math - Order of Operations - [5-7-3] - Free Educational videos for Students in K-12

Using Parenthesis in Math - Order of Operations - [5-7-3] - By Math and Science

Transcript


00:00	Hello . Welcome back . The title of this lesson
00:02	is called using parentheses . This is part one .
00:05	You might think parentheses that's something we learn . We
00:08	write down sentences in english class or in language class
00:11	. But actually we use parentheses in math all the
00:14	time . But the first time you see a set
00:16	of parentheses in math , it looks a little weird
00:18	and it scares some students . So we're going to
00:21	put that to bed here at the end of the
00:23	lesson , you'll understand what parentheses are for and how
00:25	to use them in math . So here the road
00:27	map map is we're gonna learn how to use parentheses
00:30	and then in the future lessons we're going to learn
00:32	about something called the order of operations . So we're
00:35	starting that process here . But that's the place that
00:37	we're going . So what we want to do is
00:40	talk about how do you handle it ? When for
00:42	instance , I give you a math expression that looks
00:45	like this are parentheses has opened up and you have
00:48	two plus one on the inside of the parentheses .
00:51	Why do we have these parentheses anyway ? Let me
00:54	tell you that the final answer of the whole thing
00:56	right here . This is what I want you to
00:57	remember . Any time you see parentheses in math ,
01:01	it just means you do what's inside the parentheses first
01:05	. Now in this case the only thing we have
01:07	is two plus one on the inside of the parentheses
01:09	. So it's real simple . But as we get
01:11	larger and larger and larger things added together or other
01:14	things that we're doing , we have to look at
01:16	the parentheses first and do it first . So the
01:19	only reason we ever use parentheses is when we want
01:22	to do what's inside of those first . I want
01:24	you to remember that because that's gonna be very important
01:27	. So what we have on the inside of these
01:29	parentheses is what Two plus one ? Of course ,
01:31	that's three . And so once you have just a
01:34	single item on the inside of the parentheses , you
01:36	can just drop the parentheses at this point because they
01:38	don't serve any purpose . We've already done the addition
01:40	. And so the answer to this problem is three
01:43	. Now you might look at this and say ,
01:44	well that was so easy . Why are we wasting
01:46	our time doing things like this ? It's because when
01:49	we have other things other than the parentheses , then
01:53	we need to know how to do the math in
01:55	the proper order . Right ? That's called the order
01:58	of operations . And that's what we're starting with here
02:00	. Let's say we have another problem . This one
02:02	is parentheses one plus three . Close parentheses plus two
02:08	. Now , all you need to know is a
02:10	student , is that when you see a set of
02:12	parentheses ? It just means do it first . I
02:14	want you to say it 10 times parentheses do it
02:16	first , parentheses do it . First parentheses do it
02:18	first . There's no exceptions . You always do what's
02:22	inside the parentheses first . So we ignore this .
02:25	Plus two . It doesn't have anything to do with
02:28	anything . Some people will try to add two plus
02:30	three . You don't do it that way . You
02:32	only look inside of the parentheses and do it first
02:35	. Now we have what we have here . One
02:36	plus three . Right ? One plus three is four
02:40	. And of course I'm going to wrap the parentheses
02:42	, but we could drop them at this point and
02:43	now we have on the outside plus two . Now
02:46	, we could mentally just drop the princes . They
02:48	don't serve any purpose anymore . Now we do four
02:51	plus 24 plus two is what ? 6 ? And
02:54	so the answer is six . All right . Let's
02:57	move along and see some more examples of this .
02:59	And you'll understand a little more clearly how to how
03:02	to approach it . Let's say for the next problem
03:04	parentheses two plus two . Right . And then on
03:08	the outside uh we want to multiply by three .
03:11	So here's a big dot . Dot means multiply three
03:14	. You could put an extra multiply , but we're
03:16	trying to get away from using excess from multiplying because
03:20	, you know , we already use X and Y
03:22	a lot in math . So we don't want to
03:23	get confused . We don't want to think it's a
03:25	an X variable . We want to remember that .
03:28	This is multiplied . So what do we do ?
03:31	Always the same thing . Every time I go in
03:32	, the princess do it . First two plus two
03:34	is what ? Four ? All right . So you
03:37	have a four inside of there . But we still
03:39	have to multiply by three . Now mentally we can
03:41	drop the princess here because we've already used them to
03:44	serve our purpose four times three is 12 and that
03:48	is the correct answer . Now , some students ,
03:51	if you don't know what you're doing here , we'll
03:53	start doing things like two times three is six ,
03:55	right ? Uh And then six plus two is eight
03:59	. And so you'll get the wrong answer because obviously
04:01	the answer is not the answer is 12 . If
04:03	you put this into a calculator or into a computer
04:06	, the answer you get is 12 . And if
04:08	you do it in the wrong order two times three
04:10	or six and six plus two is eight , then
04:12	you will get the wrong answer . So that is
04:14	why we have to understand that parentheses force us to
04:18	do what is inside of those parentheses first . That
04:21	is the only thing therefore , and that's why we
04:23	have an entire lesson set up . Just to talk
04:25	about parentheses . Next example let's say we have three
04:29	times one . Remember dot means multiply on the inside
04:32	of parentheses and then we're going to add to that
04:34	too . All right . We do not do the
04:37	one plus two to give me a three . We
04:39	don't do that first . We have to do what
04:40	is inside of the princess first . So we only
04:43	focus on that . What do we have inside the
04:45	princess three times one is three . And then we
04:48	still have to add that to this comes last .
04:51	And the princes we can now drop because we've used
04:55	them three plus two is of course five . The
04:57	answer is five . All right , next problem .
05:03	Let's say we have parents these 25 plus two And
05:08	then we -3 . Now you see what I mean
05:11	? It forces us to do what is inside of
05:13	here First . If you don't do that , if
05:14	you do two minus three first , that is totally
05:17	the wrong way to go . We have to do
05:19	what is inside of the parentheses first . What is
05:23	25 plus two ? 25 plus two is 27 .
05:27	Now you can put parentheses around if you want ,
05:29	but once you do the addition then we can kind
05:32	of dropped the parentheses as we have been mentally doing
05:34	up here . So we have 27 . We still
05:36	have to subtract the three so we can go down
05:39	26 25 24 will arrive at an answer of 24
05:44	that is the final answer . If you do it
05:46	in the wrong order . If you don't do what's
05:48	inside of this thing first , it is completely wrong
05:51	and that's why we're spending time to get you familiar
05:54	with that . In fact , that's why we have
05:55	the princess anyway to make sure we do this first
05:58	. Alright , next problem . Let's say we have
06:01	two times . I'll put a prince these two times
06:05	4 . All right . Now , the first thing
06:08	I'm gonna talk to you about is we know we're
06:10	gonna do what's inside of here first . All right
06:13	. But the dot out here , see how it's
06:15	two times and then a parentheses . You really don't
06:17	have to put that dot there . You could write
06:19	it right next door to the princess . And it
06:23	means the same thing when you have a number or
06:25	a letter right next to a parentheses , even though
06:28	there's no dot here . It still means multiply .
06:30	I'm just showing you that . You can go either
06:32	, you can look at it either way , These
06:33	two things are exactly the same thing . So what
06:36	do we have here ? Well , we're we know
06:38	we must do what is inside of the princess first
06:41	. We have to . So this too . With
06:43	a multiplication out here . I'll put a two dot
06:46	. Even though we don't see a dot here .
06:47	I'll put it out there . Uh We're multiplying by
06:49	. We have to do what's inside of your first
06:51	Two times four is eight . After we do that
06:54	now , two times eight . We can drop the
06:56	princes mentally is 16 . And so the answer is
06:59	16 . Alright . Again , when you have a
07:03	number or a letter right next to princes , it
07:05	means the same thing as multiply . So putting the
07:07	dot or not putting the dot . Its fine either
07:10	way . Okay . Yeah . All right . Let's
07:13	take a look at the problem . Three plus parentheses
07:18	. Nine minus seven . Again . All you have
07:22	to remember do what's inside the parentheses first . That
07:24	means the three plus . I can't even do it
07:27	yet . I have to do what is inside of
07:30	the parentheses 9 -7 is what ? 9 -7 is
07:33	too . And now I have three plus two which
07:36	is five . And so the answer is five .
07:38	That's the final answer . So , we always do
07:41	what is inside of these parentheses first ? All right
07:46	, next problem . Only a few more problems .
07:47	What about five plus six times three again . Five
07:54	plus six times three . Now you have to do
07:56	what's inside the Princes first . That means the five
07:58	plus . I can't even do it yet . I
08:00	have to do what's inside of your first six times
08:02	three is 18 . And now that I've done that
08:06	the Princes kind of disappear . They don't matter anymore
08:09	. Five plus 18 . Just go up 1920 21
08:12	, 22 , 23 . So the answer is 23
08:16	. If you ignore these princes and just go out
08:19	of order then five plus six . What is five
08:22	plus six ? That's what ? 11 ? Right .
08:24	And then if you take that 11 times three ,
08:27	that's 33 . That's completely wrong . So if you
08:30	don't do it in the right order , you will
08:31	get the wrong answer . Always do the princess first
08:34	. We do the addition last because that's not inside
08:37	the parentheses . Uh huh . All right . Only
08:40	two more problems . These are a little bit tougher
08:42	. Let's take a look at this one . Plus
08:46	now check this out two times five . Now ,
08:50	we have a closed princes here and now because of
08:52	this open when we have another close parentheses there and
08:56	then we have plus six . Now this looks very
08:58	complicated , but it's not complicated . What you need
09:01	to remember is we always do what's inside the parentheses
09:03	first , if you have two sets of parentheses ,
09:07	like one inside of the other , then you must
09:09	go to the innermost one first . Uh and you
09:13	and you you deal with that one and then you
09:14	go a little bit outward from there . So if
09:16	you ever see more than one set of princes nested
09:19	inside of each other , go to the innermost one
09:22	first . That's what we have to do . So
09:24	we have a set of princes here . So we're
09:26	gonna do what's inside of here first . But notice
09:29	what we have in here . We have a one
09:30	plus this , we have another set of princes .
09:33	So then we must go to the innermost first .
09:35	So what we're going to have is one plus what
09:38	is two times five ? That's the one we do
09:41	1st 10 . This outer set of parentheses , it's
09:44	still here . See , all I did is I
09:46	went to the innermost one and made it did the
09:49	10 . Everything else is exactly the same as it
09:51	was before . But now this inner 10 . These
09:54	interpret sees that kind of disappear and I need to
09:56	do work on the slightly outer princes . One plus
10:00	10 is what ? 11 . But then I still
10:03	have a six . So in other words , I
10:05	did the innermost princes first . Then I did the
10:08	slightly most outer princes 10 plus one being 11 .
10:12	Drop the princes at that point because they don't matter
10:14	anymore . Plus six . What is 11 plus six
10:16	? What do you get ? 17 ? Yeah ,
10:19	And that's the final answer . 11 plus 6 -
10:21	17 . So when you see multiple sets of princes
10:24	go to the innermost first . Here's our last problem
10:29	. What if we have 25 minus . Open two
10:33	sets of parentheses ? Eight plus two . Close one
10:37	set , multiply by two . And close the other
10:40	set . You see these princes go together and then
10:42	these princes go together . So I have two nested
10:45	sets of parentheses . So of course I have to
10:47	do what's inside of here first . But what is
10:49	inside of here is yet another set of parentheses .
10:51	So , I have to go and do these first
10:53	. The eight plus two is the first thing that
10:56	I'm actually gonna do . The eight plus two is
10:58	10 . I still have the times to here .
11:01	I still have these parentheses there and I still have
11:05	the 25 . Notice all I did was did this
11:08	first eight times eight plus two is 10 . But
11:10	now I have this set of parentheses to deal with
11:13	. Because you always do parentheses 1st , 10 uh
11:16	, times two is what ? 20 ? So I
11:17	have that 25 there minus 20 . I did this
11:20	next . And then finally , what is 25 minus
11:23	20 simply five ? That's the final answer . So
11:27	when you have multiple sets of princes go to the
11:29	innermost one , we did that first . The A
11:31	plus two is 10 . I still have to multiply
11:33	by the two that's inside of princes . So I
11:35	do it next . Finally , after all the princes
11:38	are gone . Then I just go left to right
11:40	, subtracting the numbers . And then I have an
11:42	answer for five . So here we have an entire
11:45	lesson just getting you comfortable with parentheses . Because I
11:48	know that the first time you see parentheses and math
11:51	, it looks weird and crazy , But it's not
11:54	weird and crazy . All you do is do what's
11:56	inside of them first , that is it , that's
11:58	all there for . And as we learn how to
12:00	deal with parentheses , when we get to order of
12:02	operations a little more complex later then we will understand
12:07	and be very comfortable with these guys . So solve
12:09	all of these yourself . When you're comfortable , go
12:11	on to part two . We'll get more practice with
12:13	parentheses in math .

Summarizer

DESCRIPTION:

Quality Math And Science Videos that feature step-by-step example problems!

OVERVIEW:

Using Parenthesis in Math - Order of Operations - [5-7-3] is a free educational video by Math and Science.

This page not only allows students and teachers view Using Parenthesis in Math - Order of Operations - [5-7-3] videos but also find engaging Sample Questions, Apps, Pins, Worksheets, Books related to the following topics.