Step by step
The question
Question: work out −3/5 ÷ (−9/10).
1 Flip and multiply
Dividing by a fraction is the same as times its flip.
Keep the first number.
Change divide to times.
Turn the second fraction upside down.
So −9/10 becomes −10/9, and divide becomes times.
2 Cancel first
Minus times minus is plus.
Before we multiply, we make the numbers smaller.
3 on top and 9 at the bottom both divide by 3.
10 on top and 5 at the bottom both divide by 5.
A top and a bottom divided by the same number: the answer stays the same.
So we multiply smaller numbers.
3 Multiply tops and bottoms
To multiply fractions, we do top times top, and bottom times bottom.
1 times 2 is 2.
1 times 3 is 3.
Can we make it simpler?
No number goes into both 2 and 3, except 1.
So it stays like this.
So the answer is 2/3.
Let's look back.
First: flip and multiply.
Then: cancel first.
Last: multiply tops and bottoms.