Cricket World Cup/Problem solving

The problem I have to solve is:

NZ won the game against Australia by 152 runs.

How many would they have to make to get to 183?

152 is what we have.

We need to change the 2 ones in 152 to a 3ones like in 183.

How many more ones do we need to add on 2 to make 3?

If I add 1 ones on 2 it will make 3ones.

Now we need to change the 5tens in 152 to 8tens like in 183.

How many more tens do we need to make the 50 into a 80?

If I add 30 to 50 it will add up to 80.

So 1 + 30  is 31.

To make 152 into 183 you will need to add 31 on 152 and that will make 183.