Before performing this trick, use soap or
Elmer's glue to put 17 on your hand or forearm.

1. Have your students write down any 2 digit number from 31 to 99.

2. Add 82.

3. Cross out the hundreds digit and add it to the remaining two digits.

4. Subtract this from your original number.


Now, take a piece of paper and burn it. Rub the ashes on your forearm to reveal a 17.