Question

How do how you cross cancel multiplying fractions

Answer 1

It's easy once you spot the ones that can cross cancel!

Say we have the fractions 8/10 and 20/23. $\frac{8}{10} \frac{20}{23}$ (it's easier to see on top of each other)

If you look diagonally , so 8 and 23 and 10 and 20, you can see that 10 and 20 have a common factor. So we divide it by the highest common factor to reduce those numbers, making it easier to multiply. 10 and 20 can become 1 and 2, dividing by 10. So now we are left with 8/1 and 2/23, and now we multiply normally going across so 16/23.

This works going both diagonals and simplifying both, but in that case it would be easier to try and simplify the fractions before cross multiplying them.

Basically: look for those diagonals and if they can be divided down by the highest common factor, go for it to make it easier to multiply normally afterwards.

Hope I helped!