Uses flexible strategies such as Break Apart to Make Ten (BAMT) and derived combinations (e.g., “7+7 is 14, so 7+8 is 15) to solve all types of problems. Can simultaneously think of numbers within a sum, and can move part of a number to another, aware of the increase in one and the decrease in another. Solves simple cases of multidigit addition (and often subtraction) by incrementing tens and/or ones.

Note: The goal for this level goes beyond simply memorizing math facts. The goal is knowing the “breakaparts,” which means the paired values that compose a target number. For example, the breakaparts for the target 4 are: 0 and 4, 1 and 3, 2 and 2. Knowing breakaparts means knowing the component parts in any order. In other words, knowing that 2 and 3 or 3 and 2 are breakaparts for the target 5. The developing combinations at this level include 5 and 7 for the target 12 and those for targets 13 or greater that are not developed earlier, such as 4 and 9 or 6 and 7 for the target 13.