Convert Fractions to Percentages - By tecmath
Transcript
| 00:0-1 | Welcome to the Tech Math channel . What we're going | |
| 00:01 | to be having a look at in this video is | |
| 00:03 | converting fractions across to percentages . Some of these are | |
| 00:06 | going to be able to be done mentally and some | |
| 00:09 | of these , you'll have to use a calculator for | |
| 00:10 | I've looked and seen videos where they say you can | |
| 00:12 | do these mentally , but really they've chosen specific examples | |
| 00:16 | where you can do that . So I'm going to | |
| 00:17 | show you how to do all types of ones , | |
| 00:19 | ones that you can do mentally and ones that you'll | |
| 00:21 | need a calculator for . So I'm gonna start out | |
| 00:23 | with the ones that you can do mentally first say | |
| 00:25 | for instance , you are given a fraction like this | |
| 00:28 | , 13 out of 20 . Now , the way | |
| 00:30 | that I would turn this into a percentage mentally , | |
| 00:33 | a percentage is a number out of 100 . So | |
| 00:36 | looking at this denominator here , really what we're looking | |
| 00:39 | for is how we can get this up to 100 | |
| 00:43 | and to do that . How would we do it | |
| 00:45 | would multiply by five . So we do the same | |
| 00:48 | to the top here . We're going to multiply at | |
| 00:50 | top number by five . So 13 times five the | |
| 00:55 | answer is 65% . Okay . And that's how I | |
| 00:59 | go about doing this . I look what I need | |
| 01:00 | to do to the denominator and then I do the | |
| 01:02 | same to the numerator and get my percentage there . | |
| 01:06 | Let's have a look at another example . So say | |
| 01:08 | for instance , I had seven out of 25 . | |
| 01:12 | Once again , how would you go and get to | |
| 01:15 | a denominator of 100 ? And you can see here | |
| 01:18 | that you would multiply by 425 times four is equal | |
| 01:22 | to 100 . So we're going to multiply Our numerator | |
| 01:26 | here also by four , And this gives us our | |
| 01:29 | percentage is 28% . Pretty simple . Right . Okay | |
| 01:34 | . What about one more of these ? Bit harder | |
| 01:36 | now , what about we go 36 out of 600 | |
| 01:41 | . Once again , the goal here is to get | |
| 01:43 | a denominator of 100 . How would you go from | |
| 01:47 | 600 get to 100 ? Well , we're not going | |
| 01:49 | to multiply this time . We're going to divide by | |
| 01:52 | six . So we're going to get our numerator here | |
| 01:55 | . And also divide by 6 , 36 divided by | |
| 01:58 | six . We get our percentage of 6% . 36 | |
| 02:02 | divided by six is equal to six . So you're | |
| 02:05 | going to see their these numbers work rather well and | |
| 02:08 | when you do that , it's really , really easy | |
| 02:09 | to look like you could do all percentages mentally , | |
| 02:12 | but that's not always going to be the case . | |
| 02:14 | I'll give you , for example , this particular one | |
| 02:17 | here , 29 out of 93 . Now , all | |
| 02:21 | of a sudden how we're gonna multiply to get 100 | |
| 02:24 | here , you can say it's almost 100 . So | |
| 02:25 | maybe it's going to be 30 31% or something like | |
| 02:28 | this , but it's not quite , we want to | |
| 02:30 | get an exact here . So how do you go | |
| 02:32 | back in this particular fraction ? As a percent ? | |
| 02:35 | Well , you're probably going to use a calculator I'm | |
| 02:37 | guessing . And the way I do this is as | |
| 02:39 | follows , Located , this fraction here means 29 divided | |
| 02:45 | by 93 . Okay , this line here means divided | |
| 02:49 | by so we're going to go top number divided by | |
| 02:51 | the bottom number . When you go 29 divided by | |
| 02:54 | 93 , you get the answer of 0.3118 . Okay | |
| 03:01 | . With big recurring decimal there there's no way you'd | |
| 03:04 | get mentally . So this is not a percentage yet | |
| 03:07 | . This is a decimal . It's a decimal which | |
| 03:10 | is a number that's out of one . Okay . | |
| 03:13 | But we want to change it to a percentage which | |
| 03:15 | is a number out of 100 . Okay . How | |
| 03:18 | would you go about doing that ? Well it's pretty | |
| 03:19 | simple . We just get this answer here and we | |
| 03:22 | multiply by 100 . Okay , so times 100 And | |
| 03:27 | we will change this decimal here into a percentage . | |
| 03:30 | It becomes 31.18% . And I just want to draw | |
| 03:34 | your attention to something here . That this decimal here | |
| 03:37 | , .3118 becomes 31.18 because we're multiplying by 100 . | |
| 03:43 | All we've really done is bounce the decimal place a | |
| 03:46 | couple of times . So quite often when we're working | |
| 03:48 | these out , what you can do is you can | |
| 03:50 | go as a fraction , You know the numerator divided | |
| 03:53 | by the denominator . And those first numbers that come | |
| 03:55 | out you can work your way around putting them into | |
| 03:58 | a percentage without doing that extra step of multiplying by | |
| 04:01 | 100 . But if you need to do that . | |
| 04:03 | So anyway , that's how you go through and change | |
| 04:06 | a fraction into a percentage . I hope this video | |
| 04:09 | was some help . Look if you need any help | |
| 04:12 | with fractions i in the description here , I have | |
| 04:15 | a link to an entire play this looking at fractions | |
| 04:18 | and I have a whole bunch of videos looking at | |
| 04:20 | percentages as well . And if you like the video | |
| 04:23 | , please remember , hit the like button . Thank | |
| 04:25 | you for watching . We'll see you next time . | |
| 04:27 | Bye . |
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Convert Fractions to Percentages is a free educational video by tecmath.
This page not only allows students and teachers view Convert Fractions to Percentages videos but also find engaging Sample Questions, Apps, Pins, Worksheets, Books related to the following topics.
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