I had hoped to use the Evaluate Expressions with Rational Numbers activity that shows parchment papers - one with a list of equations, one with fill in the blanks - where students figure out the code by solving the equations with the given a and b values. There are errors though so some of the correct answers are not there. For example the third line says a=-15 and b=2 and the expression is -2b/a which results in 4/5 but that isn't listed. It looks like they're supposed to get 5 but that would only happen with -2a/b. There's a couple like that. https://app.nearpod.com/presentation?pin=35D9A163C05F824D41F1690AFE5EE062-1