Adding Fractions math shortcut - mentally add fractions instantly - By tecmath
Transcript
00:0-1 | Good day , Welcome to Tech Mouth Channel . What | |
00:02 | we're going to be having a look at this video | |
00:03 | is a way of adding fractions . Okay , And | |
00:06 | this is a way of adding fractions without all the | |
00:08 | working out a way of doing it pretty much instantly | |
00:11 | . Okay , so sit back and work out this | |
00:14 | method . It's a pretty cool little way of doing | |
00:16 | it . So first off , how fast can you | |
00:19 | add these two fractions ? What about 2/5 plus one | |
00:25 | third . Now , have you worked out the answer | |
00:28 | to this yet ? So hopefully you're gonna get the | |
00:30 | answer of 11/15 . Did you get that ? Are | |
00:34 | you still trying to work it out ? I didn't | |
00:36 | give you very much time , did I ? But | |
00:38 | that's actually how fast you will be able to work | |
00:40 | it out . Pretty much as fast as you can | |
00:42 | write them , or fast as you can say them | |
00:43 | , you can work them out . So I want | |
00:46 | to show your method for doing this right now . | |
00:48 | So what about we start with this particular one we | |
00:51 | had here and then how did I do this ? | |
00:52 | So quickly , there's a couple of steps involved with | |
00:56 | this and you'll be doing them really , really quickly | |
00:58 | once you work these out . So first off , | |
01:01 | what we're doing is I'll get this bottom number first | |
01:04 | , That's just gonna be five times three which is | |
01:07 | 15 . Okay ? Now to get the next number | |
01:13 | , this number on the top of their answer , | |
01:15 | what I do is I multiply this number by this | |
01:18 | number of the question and then this number and this | |
01:21 | number and I add them together . Okay , So | |
01:23 | you got that . So two times three is six | |
01:28 | And then we have five times one , which is | |
01:31 | five And then we add these together . Okay ? | |
01:34 | We get our answer which is 11 . Pretty cool | |
01:38 | . Right , So I'll tell you what , let's | |
01:40 | go through a few examples of these . Give them | |
01:43 | a bit of a practice and you'll be fairly good | |
01:45 | on this . Okay , So let's I'll start with | |
01:49 | a nice easy one . What about we do a | |
01:51 | half plus one third . Okay , so same off | |
01:58 | again , you might decide I'm going to get that | |
01:59 | bottom number first . Ok , so two times three | |
02:03 | is six , Then what we do is we're multiplying | |
02:06 | this number by this number to get three and then | |
02:10 | this number by this number to get to and then | |
02:13 | we're adding them . Okay , So three Plus 2 | |
02:17 | is five . You went pretty all right with this | |
02:21 | . Okay . Now just involves keeping a few numbers | |
02:24 | in your head , which is you know , that's | |
02:26 | all part of mental math . Yeah . So it's | |
02:28 | not too bad . What about we go another one | |
02:30 | of these ? What about a quarter . And to | |
02:33 | this we're going to add two thirds . So maybe | |
02:39 | what you want to do is maybe you want to | |
02:40 | start getting the top number first and then getting the | |
02:43 | bottom number . Okay . Because that's typically how we | |
02:45 | say them . Okay , so first off , three | |
02:50 | plus eight is 11 11 12th . Okay . Because | |
02:57 | 43 to 12 and that's how you start beginning to | |
03:00 | do it mentally . Okay , how do you go | |
03:03 | with that ? Pretty good . What you might want | |
03:04 | to be doing is you might want to start pausing | |
03:06 | this because you might take a little while when you're | |
03:08 | first doing this and you do want to get correct | |
03:10 | answers . Okay . A quick wrong answer . That's | |
03:14 | no good at all either , is it ? So | |
03:15 | you you want a quick correct answer ? Okay . | |
03:18 | So what about this ? One , Couple more of | |
03:21 | these ? We've got 3/4 ended this . I'm going | |
03:24 | to add 1/5 . Okay , you got the answer | |
03:32 | yet . Okay so 15 35 15 plus 4 , | |
03:39 | 15 plus four is 19 45 20 . Pretty simple | |
03:48 | . Right Okay . What about one last one of | |
03:51 | these ? Okay . 1/8 plus two thirds . Hopefully | |
04:02 | you've already worked out the answer . Okay . Hopefully | |
04:04 | I'm slowing you down by even um speaking the rubbish | |
04:08 | that I'm speaking right now . So first off we | |
04:11 | have three Plus 16 which is 19 And 3/8 at | |
04:18 | 24 . Okay so 19 24th . Now look when | |
04:24 | we that's for adding fractions and it's a really really | |
04:27 | handy little trick . Uh Just a couple little things | |
04:30 | with this , I'm probably the major one to get | |
04:32 | is um look we haven't dealt with mixed numbers in | |
04:35 | this one so you still want to be able to | |
04:36 | deal with mixed numbers and then if you have a | |
04:38 | mixed number here you probably want to you know , | |
04:40 | work that out before you do this particular trick . | |
04:43 | So this hasn't dealt with that . The other thing | |
04:46 | is we're going to also have a bit of a | |
04:47 | look at subtraction , which is a similar sort of | |
04:49 | idea , but there's a particular order in which things | |
04:52 | have to be done . It's a little bit more | |
04:54 | particular . Okay , So what's what particular orders in | |
04:58 | particular charity do ? Um Okay . Anyway , hopefully | |
05:02 | you enjoyed that video . Oh , so you , | |
05:04 | next time . Bye . |
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