Percents and Decimals - Free Educational videos for Students in K-12

Percents and Decimals - By Anywhere Math

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00:0-1	Welcome to anywhere , Math . I'm Jeff , Jacobson
00:01	and today we're gonna talk about percents and decimals and
00:05	how to go between the two . Let's get started
00:15	. Mhm . Now , before we get into example
00:28	one let's talk a little bit about percent in general
00:31	. Well what does percent mean exactly ? So if
00:35	I look at this , 52% will per cent means
00:38	per cent cent means 100 there's 100 years in a
00:43	century , 100 legs on a centipede , 100 cents
00:47	on a dollar . So 52% means 52 per 100
00:53	. That's what it literally means . So if I'm
00:56	looking at this example right 2% as a decimal For
01:00	first one , a 52% I can write that as
01:03	52 per 100 . Well that just means 50 to
01:07	over 152 per 100 . Uh and hopefully you remember
01:13	with the fraction this line just means division , I
01:16	can think of this as 52 divided by 100 .
01:20	And hopefully , you know the shortcut to divide by
01:24	multiples of 10 . All we do is move the
01:26	decimal point to the left . If I divide by
01:29	10 I move it once to the left , divided
01:31	by 100 . I move it twice 1000 3 times
01:34	and so on . Uh and if you don't believe
01:36	me , we could actually do this . 52 divided
01:38	by 100 52 , divided by 100 . There's no
01:44	decimal point but I can put it here . All
01:47	right , that's where we go . Well 102 50
01:50	to go zero times . Now I'm going to add
01:53	a 0 , 102 , goes five times . That
01:59	would give me 500 subtract , I get 20 ,
02:02	add another zero , bring it down . 100 into
02:06	200 . Would be two times exactly . So notice
02:11	all I did was I went from Uh 52 ,
02:15	divided by 100-0.52 . I just move the decimal point
02:19	twice to the left . Okay ? Um and I
02:22	got 0.52 . So now that you know that we
02:26	don't have to bother with this , okay , so
02:30	Because basically 52% means 52 out of 100 to change
02:35	it to a decimal , it's like I divided by
02:37	100 which is moving the decimal point to the left
02:40	, which would give me 0.52 Okay , now one
02:45	mistake I see people make is that they think okay
02:48	52% that's per 100 so I can write 52% over
02:54	100 . Okay . And that's not right when we
02:58	change it to a fraction , we're getting rid of
03:01	that percent symbol . Okay , we've already we've already
03:04	said it per 100 that's why it's over 100 .
03:07	So you get rid of that if you leave it
03:09	like this , what that would mean then is 50
03:12	to over 100 ? That's this 52% divided by 100
03:17	again . So you're doing the same thing twice so
03:20	don't make that mistake . Okay so If I wanted
03:25	as a fraction it would be 50 to over 100
03:28	. But the example wants it as a as a
03:31	decimal . So all we're doing is moving the decimal
03:34	point twice to the left and get zero 52 Okay
03:39	Let's do these other ones . These ones should be
03:41	pretty quick now if we just use that . So
03:43	7% . All I need to do is move the
03:46	decimal point twice to the left . Well the decimal
03:49	point would be here . Maybe I'll do that in
03:52	red . A decimal point would be here . So
03:57	all I do is move it twice to the left
03:59	. So seven . Here's my decimal point . There's
04:04	once twice now . There's nothing here which means I
04:09	need to put a zero there to hold its place
04:12	. So I put a zero there so that my
04:14	answer . I never want to start . I never
04:17	want my answer to start with the decimal like .07
04:20	. So I put a zero here as well .
04:22	0.07 . Okay , so 7% As a decimal 0.07
04:30	or seven . Okay . And the last one C
04:35	0.5% again . Same thing . Just move it twice
04:39	to the left to make it a decimal . So
04:42	that's gonna go 12 . So I'm going to have
04:45	At the adizero there and then 05 . Right ?
04:51	The desperate point I was here . I moved it
04:54	once . Twice I got to put a zero as
04:56	a placeholder . So 0.005 . 0.005 as a decimal
05:07	. Okay , here's some to try on your own
05:16	. All right . Here's example to write the decimal
05:19	as a percent . Now we're going the other direction
05:21	instead of from percents decimals . Now we're going the
05:23	other way , decimals , 2% . If you remember
05:27	from a percent to a decimal , all we did
05:30	was move the decimal point twice to the left .
05:34	So if you're wondering how do I go from a
05:35	decimal to a percent ? I'm just doing the opposite
05:39	instead of going twice to the left , I'm going
05:41	twice to the right . Okay . And then I
05:44	just need to add the percent symbol at the end
05:47	. Okay , so 0.47 as a percent would become
05:52	once twice 47% . Really simple . Okay , so
06:01	if you want to try these on your own ,
06:02	go ahead . You composite and try them on your
06:04	own . But here we go . 0.663 as a
06:08	percent . I take this decimal point and move it
06:11	twice to the right 1 2 . So it becomes
06:15	here 66.3 percent . Make sure you add your percent
06:22	symbol at the end , right ? We're changing them
06:24	2% . And the last 11.8 . Notice 1.8 that's
06:29	greater than one . Which means my answer is going
06:33	to be greater than 100% . Right ? These were
06:36	all less than one . Which is why there's less
06:38	than 100% . But this test was greater than one
06:41	. So you would expect an answer that's greater than
06:43	100% because one Is equal to 100% . Right ?
06:48	Um so here we go . 1.8 . same thing
06:51	once twice Again notice there's nothing there . I need
06:55	to add a zero as a placeholder , so that
06:57	becomes 180% . And that makes sense because it's greater
07:04	than 100% . Here's some more to try on your
07:06	own . Thank you so much for watching , and
07:15	if you like this video , please subscribe . Yeah
00:0-1	.

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