If you are using a copier:

quick answer: If you want to enlarge something:

divide the larger number by the smaller number

and move the decimal two places to the right to get the percentage to use

Example: Block is 8 and you want to make it 8.5

8.5/8 = 1.0625

Move the decimal two places to the right: 106%

You will probably have to settle for whole numbers on your copier.

If you want to reduce something, divide the smaller number by the larger number. (You will want a number less than 1)