Art of Problem Solving Beast Academy 2A Guide and Practice $30 : Place Value : Digits, ones, tens, hundreds, breaking and regrouping, adding and subtracting 1, 10, or 100. Comparing : The number line, distance, consecutive numbers, using < and >, ordering numbers. Addition : Sums, place value strategies, counting up, adding and taking away, doubles, making 10's and 100's, friendly sums.