The Operation Sense materials develop operation sense with addition and subtraction. Students should first have a good understanding of the Number Sense materials before moving on to Operation Sense. Most of the content in the Operation Sense materials is not about teaching or even reviewing the usual algorithms for addition and subtraction. Rather, learners share and strengthen their own trustworthy strategies, which may include sequential doubling, halving, multiplying by multiples of 10, and using the commutative, associative, and distributive properties.
English versions last updated in 2025. Spanish versions last updated 2023.