North Carolina Standard Course of Study
NC.2.OA. Operations and Algebraic Thinking
Add and subtract within 20.
NC.2.OA.2. Demonstrate fluency with addition and subtraction, within 20, using mental strategies.
NC.2.NBT. Number and Operations in Base Ten
Use place value understanding and properties of operations.
NC.2.NBT.5. Demonstrate fluency with addition and subtraction, within 100, by:
NC.2.NBT.5.a. Flexibly using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
NC.2.NBT.5.b. Comparing addition and subtraction strategies, and explaining why they work.
NC.2.NBT.5.c. Selecting an appropriate strategy in order to efficiently compute sums and differences.
NC.2.NBT.7. Add and subtract, within 1,000, relating the strategy to a written method, using:
NC.2.NBT.7.b. Strategies based on place value