AoPS 2-Book Set : Art of Problem Solving Beast Academy 2C Guide and Practice 2-Book Set : Beast Academy 2C covers the following topics: Measurement: The measurement chapter only includes measuring length, and includes using a ruler, estimation, customary and metric units, conversions, mixed measures, and adding and subtracting. Strategies: Rearranging addition and subtraction, canceling, almost canceling, subtracting everything at once, using parentheses, and skip-counting. Horrible Ray endorses the Art of Problem Solving Beast Academy 2C Guide and Practice 2-Book Set for 2nd Grade and up. Horrible Ray, Horrible Books, Horrible University