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.
|Basic Operations||Multiplication and Division|
37 grandchildren per child. How many children and grandchildren are there?
If there are 49 children and each has 38 kids of their own, we can multiply 49 by 38 to
get our answer.
<<Jack voice>> "This looks like a job for Multiplication Man!"
To solve this multiplication mystery,
we're going to work backwards through 38's digits, first multiplying by 8,
then multiplying by the 3, which is actually 30.
First find 8 times 49. 8 times 9 is 72. Write the 2, carry the 7.
8 times 4 is 32, plus the carried 7 is 39.
When we write down 39 we get 392. Next multiply 3 by 49.
Repeat the steps we just did, multiplying 3 by 49, but this time write a zero before
you begin, since our 3 is actually a 30.
3 times 49 comes out to 147, so we get 1,470.
Next add 392 plus 1,470.
2 plus 0 equals 2.
9 plus 7 equals 16, so we write the 6 and carry the 1.
3 plus 4 plus the carried 1 equals 8. And 1 plus nothing equals 1.
Finally, you get our answer, 1892. Success!
That's a lot of hungry rabbits to feed. Bunny, are you going to have that carrotturkey done
in time for dinner?