Players pretend that one
of the number keys on the calculator is broken. One partner says
a number, and the other tries to display it on the calculator without
using the "broken" key.
Example:
If the 8 key is
"broken," a player can display the number 18 by pressing 9 [+]
7 [+] 2; 9 [x] 2;
or 72 [÷] 4.
