Subtraction Trick

1. Write down any number with 4 or more digits.

2. Rearrange the digits.

3. Subtract the smaller number from the larger.

4. Circle any of the digits (except a zero because it is already a circle).

5. Now give me all of the digits except the one circled (IN ANY ORDER).

Enter the digits that you have left (in ANY order but with no spaces):

Click here to run again

Click here to see why it works
 
Many thanks to Jaime Garcia Ramirez for helping me with the javascript!

Send any comments or questions to: David Pleacher