Knows number combinations to totals of 10. Quickly names parts of any whole, or the whole given parts. Doubles to 20. Uses inverses, such as a known addition combination to figure out a related subtraction combination.

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. Children learn doubles fairly early on, such as 4 and 4 for the target 8 and 5 and 5 for the target 10. Also early are combinations including 1, such as 7 and 1 for the target 8 or 9 and 1 for the target 10. Later, they learn combinations with 2 as the first addend, such as 2 and 6for the target 8 or 2 and 7 for the target 9. The last developing are combinations in which 3 and 4 are the smallest parts, such as 3 and 5 for the target 8 or 4 and 6 for the target 10.