If your students are learning about input and output functions, they need to do this activity! It is so engaging and fun, they won't want to stop! Instead of filling out input/output worksheets and finding the rule, have your children create their very own in-n-output machine. Imagine this: half the class is inside the machines, working them. And half the class is going around from machine to machine trying to guess the "secret formula". The customer sticks money into the machine, and inside the machine the student writes the new number onto a burger and sticks it out of the other slot. The customer writes the input (money) and output (burger) numbers onto their order sheet, and they try to guess the secret formula. Such a fun way to learn these patterns! Your students won't even know they're learning!