2.OA.1 USE addition and subtraction within 100 to SOLVE one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
2.NBT.5 Fluently ADD and SUBTRACT within 100 USING strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
Standards for Mathematical Practice
1. Make sense of problems and persevere in solving them.
4. Model with mathematics.
7. Look for and make use of structure.
fluent, adding to, with unknowns, equations, comparing, compose, decompose, place value, digit, ten more, ten less, add, subtract, addend, sum, equal, addition, subtraction, putting together, taking from, taking apart
and so much more!