This is an application that animates numbers being put into a function machine and "spit" out as a new number. All functions are in the form of f(x) = ax+b where a and b are between 0 and 9. The preview version always uses f(x) = x + 1.
You can pull up a table to see the x and f(x) values that have been put in. You can also reveal the function so students can see if they guessed it right.