Have different kids from each class pick a number 1-9. Each class should have 4 different digits. Make a poster of each for your wall. Have a running contest between classes.
Ask students to use those digits to find all of the numbers from 1-100. They can use +, -, *, /, and (). They can use one of their digits as an exponent. You might want to include the digit 2 in each class for this purpose. I allowed them to use the square root as well, even though technically it is a rational expon