[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.07,0:00:07.90,Default,,0000,0000,0000,,A single postage stamp costs $0.44. How much would a roll of 1000 stamps cost?
Dialogue: 0,0:00:07.90,0:00:11.71,Default,,0000,0000,0000,,And there is really a couple of ways to do it, and I'll do it both ways just to show you they both work.
Dialogue: 0,0:00:11.71,0:00:15.19,Default,,0000,0000,0000,,One is a kind of a faster way, but I want to make sure you understand why it works.
Dialogue: 0,0:00:15.19,0:00:18.25,Default,,0000,0000,0000,,And then we'll verify that it actually gives us the right answer
Dialogue: 0,0:00:18.25,0:00:21.01,Default,,0000,0000,0000,,using maybe the more traditional way of multiplying decimals.
Dialogue: 0,0:00:21.01,0:00:26.73,Default,,0000,0000,0000,,So, we're starting at $0.44. I'll just write a 0.44.
Dialogue: 0,0:00:26.73,0:00:31.56,Default,,0000,0000,0000,,Well, that's one stamp, so this is one stamp. I'll write it like this, 1 stamp.
Dialogue: 0,0:00:31.56,0:00:33.75,Default,,0000,0000,0000,,How much would 10 stamps cost?
Dialogue: 0,0:00:33.75,0:00:37.17,Default,,0000,0000,0000,,Well, if 1 stamp is $0.44, then 10 stamps,
Dialogue: 0,0:00:37.17,0:00:39.82,Default,,0000,0000,0000,,we could move the decimal to the right one place,
Dialogue: 0,0:00:39.82,0:00:43.75,Default,,0000,0000,0000,,and so it would be, and now this leading zero is not that useful,
Dialogue: 0,0:00:43.75,0:00:51.53,Default,,0000,0000,0000,,so it would now be $4.4. Or if you want to make it clear, it would be $4.40.
Dialogue: 0,0:00:51.53,0:00:56.12,Default,,0000,0000,0000,,Now, what happens if you want to have a hundred stamps? 100 stamps.
Dialogue: 0,0:00:56.14,0:00:58.08,Default,,0000,0000,0000,,Well, the same idea is going to happen.
Dialogue: 0,0:00:58.08,0:01:02.60,Default,,0000,0000,0000,,We're now taking 10 times more so we're going to move to the decimal to the right once.
Dialogue: 0,0:01:02.60,0:01:07.18,Default,,0000,0000,0000,,So, a hundred stamps are going to cost, are going to cost $44.00.
Dialogue: 0,0:01:07.18,0:01:08.99,Default,,0000,0000,0000,,And this should make sense for you.
Dialogue: 0,0:01:08.99,0:01:15.90,Default,,0000,0000,0000,,If one stamp is 44 hundreths of a dollar, then a hundred stamps are going to be
Dialogue: 0,0:01:15.90,0:01:20.59,Default,,0000,0000,0000,,44 hundreths of a hundred dollars, or $44. Or you could view it as
Dialogue: 0,0:01:20.59,0:01:22.65,Default,,0000,0000,0000,,we've just moved the decimal over one place.
Dialogue: 0,0:01:22.66,0:01:25.65,Default,,0000,0000,0000,,So if we want a thousand stamps, if we want 1000 stamps,
Dialogue: 0,0:01:25.65,0:01:28.17,Default,,0000,0000,0000,,we would move the decimal to the right one more time.
Dialogue: 0,0:01:28.17,0:01:35.29,Default,,0000,0000,0000,,Moving the decimal to the right is equivalent to multiplying by ten. So then it would be $440.
Dialogue: 0,0:01:35.31,0:01:40.61,Default,,0000,0000,0000,,Now, we could put, add another trailing zero just to make it clear that there is no cents over here.
Dialogue: 0,0:01:40.64,0:01:44.06,Default,,0000,0000,0000,,So if you want to do it really quickly, you could've started with $0.44.
Dialogue: 0,0:01:44.13,0:01:48.28,Default,,0000,0000,0000,,And you say, look, I'm not multiplying by ten. I'm not multiplying by a hundred.
Dialogue: 0,0:01:48.31,0:01:53.22,Default,,0000,0000,0000,,I'm multiplying by a thousand. You're going to have to put another trailing zero over here.
Dialogue: 0,0:01:53.27,0:01:58.56,Default,,0000,0000,0000,,And you would move the decimals from over here to over here.
Dialogue: 0,0:01:58.56,0:02:04.72,Default,,0000,0000,0000,,You've essentially multiplied this times ten times ten times ten, which is a thousand.
Dialogue: 0,0:02:04.72,0:02:10.45,Default,,0000,0000,0000,,So then this would become $440.
Dialogue: 0,0:02:10.47,0:02:14.96,Default,,0000,0000,0000,,So let's verify that this works the exactly the same if we multiply the traditional way
Dialogue: 0,0:02:14.96,0:02:24.86,Default,,0000,0000,0000,,the way we multiply decimals. So if you have 1000 times $0.44.
Dialogue: 0,0:02:24.88,0:02:33.06,Default,,0000,0000,0000,,So you start over here. 4 times 0 is 0, 4 times 0 is 0, 4 times 0 is 0, 4 times 1 is 4.
Dialogue: 0,0:02:33.07,0:02:36.20,Default,,0000,0000,0000,,Or you could just say, hey, this was 4 times a thousand.
Dialogue: 0,0:02:36.20,0:02:39.82,Default,,0000,0000,0000,,Then we're going to go one place over so we're going to add a zero.
Dialogue: 0,0:02:39.85,0:02:47.95,Default,,0000,0000,0000,,And we, once again, we're going to have 4 times 0 is 0, 4 times 0 is 0, 4 times 0 is 0, 4 times 1 is 4.
Dialogue: 0,0:02:47.95,0:02:51.22,Default,,0000,0000,0000,,Or we just did 4 times a thousand. So that is 4000,
Dialogue: 0,0:02:51.22,0:02:54.19,Default,,0000,0000,0000,,if you don't include this zero that we added here ahead of time
Dialogue: 0,0:02:54.19,0:02:57.00,Default,,0000,0000,0000,,because we're going one place to the left.
Dialogue: 0,0:02:57.02,0:03:01.08,Default,,0000,0000,0000,,And then we have nothing left. I haven't at all thought about the decimals right now.
Dialogue: 0,0:03:01.11,0:03:05.86,Default,,0000,0000,0000,,So far I've really just viewed it as a thousand times 44. I've been ignoring the decimal.
Dialogue: 0,0:03:05.86,0:03:08.17,Default,,0000,0000,0000,,So if it was a thousand times 44,
Dialogue: 0,0:03:08.17,0:03:14.79,Default,,0000,0000,0000,,we would get 0 plus 0 is 0, 0 plus 0 is 0, 0 plus 0 is 0, 4 plus 0 is 4,
Dialogue: 0,0:03:14.79,0:03:19.50,Default,,0000,0000,0000,,4 plus nothing is 4. And if you ignore the decimal, that makes a lot of sense.
Dialogue: 0,0:03:19.50,0:03:24.44,Default,,0000,0000,0000,,Because a thousand times 4 is 4000 and a thousand times 40 would be 40 000.
Dialogue: 0,0:03:24.44,0:03:30.52,Default,,0000,0000,0000,,So you would get 44 000. But this of course is not a 44. This is a 44 hundreths.
Dialogue: 0,0:03:30.52,0:03:34.31,Default,,0000,0000,0000,,We have, between the two numbers, two numbers behind the decimal point.
Dialogue: 0,0:03:34.31,0:03:38.37,Default,,0000,0000,0000,,So we need to have two numbers behind or to the right of the decimal point in our answer.
Dialogue: 0,0:03:38.37,0:03:40.80,Default,,0000,0000,0000,,So one, two. Right over there.
Dialogue: 0,0:03:40.80,9:59:59.99,Default,,0000,0000,0000,,So, once again, we get $440.00 for the thousand stamps.