Four critical areas of instruction in Second Grade are:

1. Extending understanding of base-ten notation

2. Building fluency with addition and subtraction

3. Using standard units of measure

4. Describing and analyzing shapes

Second Grade students also work toward fluency with addition and subtraction within 20 using mental strategies and within 100 using strategies based on place value, properties of operations, and the relationship between addition and subtraction. They know from memory all sums of two one-digit numbers.

(California Mathematics Framework, 2013, p. 119)