Adding and Subtracting Fractions with a Different Denominator - By tecmath
Transcript
| 00:0-1 | Hey , welcome to the Tech Math channel . What | |
| 00:01 | we're going to be having a look at this video | |
| 00:03 | is adding and subtracting fractions . This is the second | |
| 00:05 | part where we're going to now have a look at | |
| 00:07 | adding and subtracting fractions with different denominators . That is | |
| 00:11 | different bottom numbers . An example here is we can | |
| 00:15 | get 3/8 into this , we're going to add one | |
| 00:18 | half and you're going to notice first off that we | |
| 00:21 | have different denominators here . So how do we go | |
| 00:24 | about adding and subtracting when we have different denominators ? | |
| 00:27 | Well , it's not too hard . What you really | |
| 00:29 | have to get with this is that we are going | |
| 00:31 | to play around with either one or both fractions here | |
| 00:35 | . Where are we actually going to be using this | |
| 00:36 | idea of equivalent fractions to make these denominators the same | |
| 00:40 | ? I'll show what I mean by this . So | |
| 00:41 | if we look for a common number that both to | |
| 00:45 | and go into the lowest one we could think of | |
| 00:47 | , you can think , okay , well both of | |
| 00:48 | these numbers go into eight . Uh Eight goes into | |
| 00:52 | eight ones , so we're not gonna need to change | |
| 00:53 | this one and two goes into 84 times because two | |
| 00:57 | goes into 84 times . We multiply both the top | |
| 01:01 | and the bottom part of the fraction here . By | |
| 01:04 | that four to move it up to eight , we're | |
| 01:06 | gonna end up with equivalent fraction for a half , | |
| 01:08 | which is one times four is four and two times | |
| 01:11 | four which is eight . So what do we have | |
| 01:14 | now ? If I was to rewrite this whole fraction | |
| 01:17 | now , I could say , okay , we now | |
| 01:19 | have 3/8 Plus 4/8 , and we can work this | |
| 01:24 | out really easy because now what we have is we | |
| 01:27 | have a common denominator here , three plus four is | |
| 01:31 | equal to seven . And remember that the eight stays | |
| 01:35 | the same , that denominator stays the same when we're | |
| 01:37 | adding . So that's how we do this . It's | |
| 01:39 | pretty simple . Right ? What about I give you | |
| 01:41 | another example ? Okay another example we're going to go | |
| 01:44 | 5/6 and we're going to take away one quarter . | |
| 01:49 | Once again you're going to know that we have different | |
| 01:51 | denominators here . So what we're going to do first | |
| 01:54 | off is we're going to change these using the idea | |
| 01:56 | of equivalent fractions to get denominators the same on the | |
| 02:01 | base . So first off , what's a common number | |
| 02:03 | that both six and four go into ? Yeah the | |
| 02:07 | lowest one I can think of is 12 . Okay | |
| 02:10 | . What we multiply six by here to get 12 | |
| 02:13 | ? And you can say Okay would multiply by two | |
| 02:15 | . So we're gonna multiply the top and the bottom | |
| 02:17 | by two . Okay what would we multiply by four | |
| 02:21 | here to get 12 ? Okay , that's three . | |
| 02:23 | So multiplied by three , multiplied by three . So | |
| 02:26 | what have we got now when we do this ? | |
| 02:29 | Okay , five times 2 is equal to 10 . | |
| 02:32 | Six times two is equal to 12 . So that's | |
| 02:35 | the equivalent of production for 56 is 10/12 . We're | |
| 02:38 | going to subtract from this . Well , this fraction | |
| 02:41 | here , one times three is three And four times | |
| 02:45 | 3 is 12 . Awesome . We've got Common denominators | |
| 02:49 | here , lets us go through and do this . | |
| 02:51 | So 10 take away three is equal to seven and | |
| 02:55 | this denominator stays the same so they're not too bad | |
| 02:59 | . All right . The last time , the example | |
| 03:01 | I'm going to give you is where we're going to | |
| 03:03 | be using mixed numbers and these aren't too bad either | |
| 00:0-1 | . |
Summarizer
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OVERVIEW:
Adding and Subtracting Fractions with a Different Denominator is a free educational video by tecmath.
This page not only allows students and teachers view Adding and Subtracting Fractions with a Different Denominator videos but also find engaging Sample Questions, Apps, Pins, Worksheets, Books related to the following topics.
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