How can that possibly mean anything?
gcf = (13 (7 % 13));
on the line before and on the line after your code to preserve formatting. See the FAQ for other formatting options. Use the Preview tab to see what the result will look like. If you don't add the 'code' tags you are on your own. You can't automate what you can't do manually. So the first step is to perform your process MANUALLY 1. select a sample value for 'val1' 2. select a sample value for 'val2' 3. show, using pseudo-code or a formula, how the result is to be computed