Put this on someone else's calculator
When they try to do a math problem, if the answer would be an integer, it randomly changes it to another integer, and if the answer wouldn't be an integer, it changes it to a random number.
I would also suggest editing their other programs and changing "Stop" to whatever you named this program (if you want to be extra evil)
I actually did this to someone… I'm so mean.
Code: (download is useless because they might get suspicious if their calc. stopped working after you plugged it into your computer.)