The lesson where they had the 4th graders ESTIMATE by rounding how much change they'd get back after a purchase put me over the top! So, for an everyday use, I guess a quick look at the money would tell you if you got about the right amount of money back, give or take a little.
Math is my S favorite subject, yet he is consistently frustrated by it because he say's the lessons don't make any sense. We look at it and scratch our heads. It seems as if the directions are designed to confuse the reader.