Grade 2
Domain Operations and Algebraic Thinking
Cluster Add and subtract within 20.
Standard Fluently add and subtract within 20 using mental strategies.<span class='footnote'>See standard 1.OA.6 for a list of mental strategies.</span> By end of Grade 2, know from memory all sums of two one-digit numbers.

2.OA.B.2. Fluently add and subtract within 20 using mental strategies.See standard 1.OA.6 for a list of mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.