Main content

## Dividing decimals

Current time:0:00Total duration:2:37

# Dividing whole numbers to get a decimal

CCSS.Math:

## Video transcript

Let's take 63 and
divide it by 35. So the first thing
that we might say is, OK, well, 35
doesn't go into 6. It does go into 63. It goes into 63 one time,
because 2 times 35 is 70, so that's too big. So it goes one time. So let me write that. 1 times 35 is 35. And then if we were to subtract
and we can regroup up here, we can take a 10 from the
60, so it becomes a 50, give that 10 to the
3, so it becomes a 13. 13 minus 5 is 8. 5 minus 3 is 2. So you could just say,
hey, 63 divided by 35-- let me write this. You could say 63 divided by
35 is equal to 1 remainder 28. But this isn't so satisfying. We know that the
real answer is going to be one point something,
something, something. So what I want to
do is keep dividing. I want to divide this thing
completely and see what type of a decimal I actually get. And to do that, I
essentially have to add a decimal here and
then just keep bringing down decimal places to the
right of the decimal. So 63 is the exact
same thing as 63.0, and I could add as many zeroes
as I might want to add here. So what we could do
is we just make sure that this decimals
right over there, and we can now bring down a
zero from the tenths place right over here. And you bring down that zero,
and now we ask ourselves, how many times does
35 go into 280? And, as always, this is a
bit of an art when you're dividing a two-digit number
into a three-digit number. So let's see, it's
definitely going to be-- if I were to say-- so
40 goes into 280 seven times. 30 goes into 280
about nine times. It's going to be between
7 and 9, so let's try 8. So, let's see what
35 times 8 is. 35 times 8. 5 times 8 is 40, 3 times
8 is 24, plus 4 is 28. So it actually
works out perfectly. So 35 goes into 280
exactly eight times. 8 times 5, we already
figured it out. 8 times 35 is exactly 280, and
we don't have any remainder now, so we don't have to bring
down any more of these zeroes. So now we know exactly
that 63 divided by 35 is equal to exactly 1.8.