0:03 Some of you haven't multiplied decimals
0:05 since the Reagan administration. So,
0:07 let's practice. Now, you don't have to
0:10 stack them. That's just for addition or
0:12 subtraction. So, we're going to start on
0:16 the bottom right there. Okay. 4 * 2, 8.
0:22 Then 4 * 1, 4. 4 * 4, 16. Now, the
0:24 second number gets a little hairy
0:26 because you may remember you have to put
0:29 a zero right there. So once you put it
0:33 then you could just do 3 * 2 6 and carry
0:40 on your merry way. 3 * 1 3 3 * 4 12
0:42 from here you may be thinking okay I
0:45 think it's addition maybe subtraction
0:50 but multiplication is addition because 3
0:54 * 2 same thing as 3 + 3 or two added
0:56 three times. So therefore, with these
0:58 guys, we're going to add. And then
1:02 you'll start on the right side. 8 + 0 8
1:09 4 + 6 10 carry the 1. 1 + 6 7 + 3 10
1:15 carry the 1. 1 + 1 2 + 2 4 and 1. Now
1:17 we're going to take care of the decimal
1:19 at the end of the problem. You just
1:21 count how many numbers are to the right
1:24 of the decimal in the original. one,
1:27 two, three. Or another way that people
1:30 do it is they count in one, two like
1:34 that and one like that for a grand total
1:37 of three. Then it's a reminder, you're
1:39 going to count in one, two, three to the
1:41 left for the final and put it right
1:45 there. So 14.008
1:48 and that is our final answer there.
1:54 Okay, let's do it. 8 * 5 40 carry the 4.
2:00 8 * 7 56 + 4 60 carry the 6.
2:04 8 * 9 72 + 6 78.
2:06 And then don't forget your zero. And
2:12 then you're good. Okay. 1 * 5 5 1 * 7 7.
2:17 And 1 * 9. Then let's add these up.
2:22 right side. Zero, five, 8 + 7, 15. Carry
2:24 the one. And then you could do a little
2:30 1 + 9 action. 10 + 7 17.
2:32 Okay, let's count the decimals. Top
2:35 number, three of them. Middle one or
2:38 bottom number, one of them. Grand total
2:41 of four. Count from right to left. And
2:43 right there.
2:45 By the way, if these are written next to
2:47 each other, you'll always stack the one
2:50 that has less numbers underneath and
2:52 then you can do it like that.
2:55 Let's check out a division one here.
2:58 What is the value of this? Now, we're
3:01 going to use long division. Which one
3:04 goes where for this problem? If you were
3:06 thinking two on the outside, that's
3:10 right. And then 10 on the inside. In
3:11 other words, whatever you're dividing
3:15 by, that thing goes on the outside.
3:17 Okay? So, 0.03
3:19 on the outside, the other one on the
3:22 inside. You're going to go ahead and
3:24 move it to the end of the number on the
3:27 outside. So, two places to the right.
3:29 That'll just turn it into a whole number
3:32 three. Since we moved it twice to the
3:33 right, we're going to move the one on
3:35 the inside twice to the right. Right
3:38 there. And then you can just bring it
3:39 straight up.
3:41 From here, this is the same thing as
3:45 this problem. Much cleaner, much nicer.
3:47 So, just to recap, you move the decimal,
3:50 then you get into the division.
3:53 Now, three into five. That one's just
3:56 going to go one time. So, we did the
4:00 division. And then multiplication. 1 *
4:03 3. Three. Then you're going to move to
4:06 subtraction. So you're always going to
4:08 do them in that order over and over
4:11 again. Okay, subtracting those two, we
4:13 get two. But this is where you bring
4:17 down the next number. So 24
4:24 3 into 24 8. 8 * 3 24. Subtract zero.
4:26 And we'll go ahead and bring down the
4:28 next number. But let's pause here
4:31 because this is important. 3 doesn't go
4:35 into two. So therefore, it goes in zero
4:38 times. So if you bring down the helper
4:40 number, but it still doesn't help, then
4:43 it's got to be a zero there.
4:46 Okay, now no worries. We're just going
4:48 to keep going. Let's put our decimal and
4:51 let's bring down the seven instead.
4:55 Okay, 3 into 27. That'll go nine times.
4:59 9 * 3 27. No remainder. And that is it.
5:02 Once you bring down the last number, you
5:05 don't have a remainder. Then that is our
5:08 answer 180.9.
5:11 One way to contextualize this is how
5:16 many times can three cents go into $542.
5:19 You could just think of it like money
5:22 and it can go in 180 times. So that's
5:25 why that answer makes sense.
5:28 And our last one. Now, you may be
5:29 thinking, "Hey, man, what's the deal? I
5:31 thought this was a decimal video. What's
5:33 with the fractions?" Well, we're going
5:35 to convert them into decimals. That'll
5:39 be the easiest way to compare these. So,
5:40 once again, we're going to use long
5:42 division here. But the way we could say
5:46 this is four / five. So, therefore, five
5:50 is on the outside, four on the inside.
5:52 Okay. How many times can five go into
5:55 four? Well, it's a little discouraging
6:01 because zero times 0 * 5 0 subtract and
6:03 we get right back to where we started.
6:06 But lucky for us, we got an ace up our
6:09 sleeve because four is the same thing as 4.0.
6:11 4.0.
6:13 So therefore, we could bring down the
6:16 zero. Continue on. Now, if you're not
6:19 sure how many times five goes into 40,
6:22 you could just count by fives. One, two,
6:26 three, four, five, six, seven, eight. So
6:30 bring up the decimal and eight times. So
6:33 eight times five, perfect 40. Subtract
6:38 those but no remainder. So we're done.
6:40 In other words, four fths is the same
6:44 thing as 0.8. Then we got 90 cents, 80
6:48 cents, 77 cents. So we're well on our
6:52 way. But in terms of money, 3 over4,
6:54 same thing as three quarters. So that's
6:58 actually 75 cents there. But let's go
7:00 ahead and verify it. We'll do our long
7:03 division here. So there it is. There's
7:06 our 75 cents. And we're good. So
7:10 finally, smallest to biggest, we got 75
7:13 cents. It's going to start with 3/4s.
7:16 Could be B, could be D, but then the
7:20 next one's got to be 77. So, it's got to
7:25 be B because then 4 fths, 80 cents, 90
7:28 cents, and we're good. So, keep an eye
7:31 out for all of these types for the no
7:34 calculator section. Good luck. Let me
7:36 know what issues you run into. You got
7:38 these. We'll see you in the next video. Toodles.
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