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# Dividing a decimal by a power of 10: pattern

Discover a pattern when dividing by powers of 10. Created by Sal Khan.

Video transcript

In the last video, we divided
100 into 99.061, and we did it the manual way. We did it the long
division way. In this video, I just want to
show you a quick shortcut because we're dividing something
by a power of ten. If I have 99.061, if I multiply
by a power of ten, I'm going to make the
number bigger. Every time I multiply by 10, the
decimal would shift to the right by one spot. So we could say, 99.061
times 10 is going to be equal to 990.61. Notice we just moved
the decimal over to the right by one. If I were to do-- I'll just
arbitrarily switch colors-- 99.061 divided by 10, we're
going to shift the decimal in the other direction. This is going to be 9.9061. So when we divide by 100, we're
dividing by 10 twice. We're shifting to
the left twice. So if we start with 99.061
divided by 100-- let me just write it like this. We've already written
the problem. If we want to divide this by
100, moving it one spot to the left will divide it by 10, and
then moving another spot to the left will divide
it by 10 again. So 99.061 divided by 100 is
going to be equal to 0.99061. We're just going to shift the
decimal to the left by two. And we might want to put a
leading zero here, just so it makes it a little bit
easier to read.