### Video Transcript

Write nine over 40 as a
decimal.

To convert a fraction into a
decimal, we need to remember that the horizontal line in the fraction means
divide. So nine over 40 means nine divided
by 40. As we do have access to a
calculator in this paper, we can just type this sum into our calculator and it gives
0.225. We don’t need to round this answer
in any way. So our final answer is 0.225.

Now, remember this is a calculator
question. So the method that we’ve used is
perfectly fine. But suppose we didn’t have a
calculator and we needed to convert nine over 40 into a decimal. We’d need to think of how we divide
nine by 40 without a calculator.

As 40 is equal to four multiplied
by 10, to divide by 40, we can therefore divide by four and then divide by 10. To divide nine by four first of
all, we could use a short division method.

Four goes into nine twice with a
remainder of one. So we have to add a decimal point
and a zero after it and then carry the one into this column. Four goes into 10 twice with a
remainder of two. So we have to add another zero
after the decimal point and carry this remainder of two. Four goes into 20 five times with
no remainder. So our division can stop here. Nine divided by four then is equal
to 2.25.

Remember then we wanted to divide
by 40. So now, we need to divide this
answer by 10. When we divide a number by 10, it
gets smaller. And in fact, to divide by 10, we
can keep the decimal point fixed and move all of the digits one place to the
right. This gives 0.225, which is the same
as the answer we found when doing the division on our calculator.

The key point that you need to
remember in this question is that that horizontal line in a fraction means you have
to divide the number on the top, the numerator, by the number on the bottom, the
denominator.