Percentages made easy - fast shortcut trick! - By tecmath
Transcript
| 00:0-1 | Welcome to the Tech Math channel . What we're going | |
| 00:02 | to be having a look at this video as a | |
| 00:03 | way of really rapidly working out percentages of a number | |
| 00:06 | . Okay . And this is something you can easily | |
| 00:08 | do in your head as you , as you're living | |
| 00:11 | a day to day lives without having to pull out | |
| 00:13 | a phone or anything like that to work it out | |
| 00:14 | a calculator or anything like this . So give an | |
| 00:17 | example this to say You got something like 30 percent | |
| 00:23 | of 40 . Look straight away . You should be | |
| 00:26 | able to look at the answer to this as 12 | |
| 00:30 | . I'll tell you how I do this and this | |
| 00:32 | is literally how quickly you can do these . Um | |
| 00:35 | , it's because of this look just a quick bit | |
| 00:38 | of an explanation . This will take a minute . | |
| 00:40 | So I apologize . If you have a short attention | |
| 00:42 | span , you might want to skip over a minute | |
| 00:44 | and I'll just get to the nuts and bolts . | |
| 00:45 | But this is really worth knowing how to do . | |
| 00:47 | Um , so say 38 of a percent means 30 | |
| 00:50 | out of 100 okay , of times and 40 we've | |
| 00:56 | got 40/1 . So this is typically that's set up | |
| 00:58 | . They used to get you probably doing at school | |
| 01:00 | , maybe they're getting you're doing now when you work | |
| 01:02 | out percentages . And So we can start canceling zeros | |
| 01:06 | out because this means divided by hundreds of 30 , | |
| 01:09 | divided by 10 . Okay , so we're providing both | |
| 01:13 | bits by their by 10 . So 30 divided by | |
| 01:15 | 10 and 300 divided by 10 . And we're dividing | |
| 01:18 | the 40 here , also by 10 . Okay , | |
| 01:20 | so we're ending up with three times 4 you're going | |
| 01:23 | to see here That is of divided by 10 divided | |
| 01:26 | by 10 . Okay . And then I'm just multiplying | |
| 01:29 | them out . So three times four is 12 . | |
| 01:31 | I'm only looking at the first parts of these numbers | |
| 01:34 | here , pretty easy . Right , So what about | |
| 01:38 | , we'll give you a go doing this . There's | |
| 01:40 | some people are already going to look at this and | |
| 01:41 | go , hey , I do that already . And | |
| 01:42 | that's what we're gonna be having a look at this | |
| 01:44 | video . So if you're already good with that , | |
| 01:46 | that's great . Um This is meant for if you're | |
| 01:48 | not and this is brand new . Okay , So | |
| 01:50 | say you had something like 20% of let's go 18 | |
| 01:58 | . Actually stick to bigger numbers to start off . | |
| 02:01 | I'll show you how to do all these other ones | |
| 02:02 | in a sec . Okay ? So say you had | |
| 02:04 | 20% of 18 The way that you go about doing | |
| 02:07 | these once again you can cancel that . You're zeros | |
| 02:10 | . Okay ? So two times 18 Get the answer | |
| 02:13 | of 36 . Right , well that you do one | |
| 02:19 | of these . Okay , so say it was something | |
| 02:22 | like what about 50% of say we had 40 so | |
| 02:32 | hopefully what you're doing is you counted on those two | |
| 02:34 | zeros ? You've got five times four . Yeah , | |
| 02:37 | it's just 20 . That's really easy , right ? | |
| 02:39 | If you if you haven't been doing that method already | |
| 02:41 | , you probably feel like you've been a little bit | |
| 02:42 | robbed that you haven't known it already . Right ? | |
| 02:45 | Anyway , I'll show you what you do once they | |
| 02:47 | start to get a little bit harder . What does | |
| 02:48 | that say I had ? Because occasionally not everything is | |
| 02:52 | going to be these multiples of 10s , are they | |
| 02:54 | ? So look uh It would say something like let's | |
| 03:00 | go back to that one . We had before 20% | |
| 03:02 | of 18 . That was the one I crossed out | |
| 03:05 | rapidly before when I realized I was getting ahead of | |
| 03:08 | myself . If you're doing this one . Okay . | |
| 03:11 | So we're dividing by 10 and we're getting too were | |
| 03:14 | divided by 10 here . Huh ? And we're getting | |
| 03:17 | 1.8 you're gonna see this ? Each time we canceling | |
| 03:19 | at those Zeros were divided by 10 . Okay . | |
| 03:21 | So we're ending up with two times 1.8 . two | |
| 03:25 | times 1.82 groups of 1.8 Is going to be 3.6 | |
| 03:31 | . So do you get that ? I'll give you | |
| 03:32 | another example of where you might do this and then | |
| 03:35 | we'll get you doing one Or you might feel confident | |
| 03:37 | to this yourself . So you are due 30 of | |
| 03:44 | 12 . Okay , So we get rid of that | |
| 03:49 | zero . We jump the decimal place here . So | |
| 03:51 | three times 1.2 we're going to get the answer of | |
| 03:56 | 3.6 . Okay . What about you could want to | |
| 04:04 | go get rid of that there . What about we | |
| 04:06 | do so say I'll give you something like 40 of | |
| 04:16 | Let's go 15 . Hopefully , you know the answer | |
| 04:20 | is already right , pause , it worked it out | |
| 04:24 | . Get rid of that . zero there . Just | |
| 04:26 | that one there Four times 1.5 We'll get the answer | |
| 04:30 | of six . Okay . How do you go with | |
| 04:33 | that ? So it's not too bad . So it's | |
| 04:35 | a really handy little method for just working out day | |
| 04:38 | today . Now , once we start to get two | |
| 04:40 | numbers , like they were working at say , uh | |
| 04:43 | , 65 of 82 All of a sudden you're going | |
| 04:50 | to notice that it does get a little bit harder | |
| 04:54 | . Yeah . So look , I've got a video | |
| 04:56 | and I'll put a link up with how you might | |
| 04:58 | deal with these because this one's a little bit of | |
| 05:00 | a special case . You're probably , if you're looking | |
| 05:02 | at this still , you're probably not going to be | |
| 05:03 | at the stage where you're going 6.5 times 8.2 and | |
| 05:08 | doing that in your head , okay ? But hey | |
| 05:11 | , even if you're at this stage , you can | |
| 05:12 | pull something calculator out and do that . You may | |
| 05:14 | be better off than where you were , but I've | |
| 05:16 | got a video , I'll put a leg up and | |
| 05:17 | how you can deal with these and start working these | |
| 05:19 | out in your head as well . Okay ? Um | |
| 05:23 | , anyway , by the way , um , 65% | |
| 05:25 | of 82 . The answer to that is , uh | |
| 05:29 | , 53.30 just in case you had worked that out | |
| 05:34 | . Okay . Anyway , hopefully there was some help | |
| 05:37 | to you . Hope you enjoyed the video . See | |
| 05:39 | you next time . Bye . |
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Percentages made easy - fast shortcut trick! is a free educational video by tecmath.
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