Question

How do you evaluate `20(1/2 times35)`?

Answer 1

`350`

Explanation:

Notice that the brackets are not necessary because the only operation is multiplication.

Dividing (cancelling) first is a GREAT idea, because it makes the numbers smaller.

`20 xx 1/2 xx 35 " "` gives `cancel20^10 xx 1/cancel2 xx 35`

which is very convenient because multiplication by 10 is a breeze.

This can be seen to give 350.

This type of calculation can be done by inspection rather than having to write it out.