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Long Multiplication 1788 Views
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Description:
What do you do when you have to multiply large numbers but you can’t use a calculator? Long multiplication, of course. This video covers how to do a long multiplication problem to solve an intimidating math problem. It’s really a lot simpler than it looks if you just take it one step at a time—and always remember to carry your numbers.
Transcript
- 00:04
Long Multiplication, a la Shmoop. Ah, the holidays. A time to come together
- 00:10
to wage war over politics and tell the kids they're disappointing.
- 00:14
Jack and Bunny Rabbit come from a very fertile family.
- 00:17
Which is why figuring out how much carroturkey to cook for Bunsgiving makes Bunny completely
- 00:18
hare-brained. The Rabbits have 49 children, and there are
Full Transcript
- 00:20
37 grandchildren per child. How many children and grandchildren are there?
- 00:26
If there are 49 children and each has 38 kids of their own, we can multiply 49 by 38 to
- 00:32
get our answer.
- 00:32
<<Jack voice>> "This looks like a job for Multiplication Man!"
- 00:36
To solve this multiplication mystery,
- 00:39
we're going to work backwards through 38's digits, first multiplying by 8,
- 00:44
then multiplying by the 3, which is actually 30.
- 00:48
First find 8 times 49. 8 times 9 is 72. Write the 2, carry the 7.
- 00:57
8 times 4 is 32, plus the carried 7 is 39.
- 01:03
When we write down 39 we get 392. Next multiply 3 by 49.
- 01:09
Repeat the steps we just did, multiplying 3 by 49, but this time write a zero before
- 01:15
you begin, since our 3 is actually a 30.
- 01:19
3 times 49 comes out to 147, so we get 1,470.
- 01:37
Next add 392 plus 1,470.
- 01:41
2 plus 0 equals 2.
- 01:44
9 plus 7 equals 16, so we write the 6 and carry the 1.
- 01:49
3 plus 4 plus the carried 1 equals 8. And 1 plus nothing equals 1.
- 01:56
Finally, you get our answer, 1892. Success!
- 02:01
That's a lot of hungry rabbits to feed. Bunny, are you going to have that carrotturkey done
- 02:26
in time for dinner?
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