First, you have to move the decimal point before you divide like normally. You need to move it so that the left number is a whole number.
So, 6.39/0.9 would turn into 63.9/9.
12.75/2.5 would turn into 127.5/25.
You just move the decimal how ever many times to the right to make it a whole number. In this case, it is 1 decimal place.
