This offering is a "mathacrostics" puzzle affording teachers and students another opportunity to practice and/or review using differentials to approximate. It is intended to help students prepare for the no-calculator part of the AB AP calculus test. For this reason (and several others) a sheet with complete solutions of all problems given in the puzzle will be included. This puzzle is one of 30 puzzles created for a "first quarter college calculus-type course" - in high school, home, or college. Along with the puzzle and solution sheet I will be including a more detailed explanation of my goals in the No Calc Calc Puzzle Book and a Table of Contents that includes the topics (and answers) of the other 29 puzzles that can be bought individually or as a book on TpT - and eventually on our Value Added Publishing website.