3Professor Tangent is very forgetful and has accidentally put the lunch orders for the class in the paper shredder. The class collects all the little strips, and they add up all the different sections to make sure the total equals the number of kids in the class. They create a number line to get the total. But Chef Addie just made them all pizza instead Simple sentences and easy-to-understand exercises help make learning about addition understandable and fun.