Count back & use the relationship between addition and subtraction to subtract within 20. Warm up with a Mystery Math Mistake to find the error in DC's addition. Use ...

A thorough understanding of addition and subtraction requires knowledge of the inverse relation between these operations. According to Piaget (1952), any inverse relation poses a significant challenge ...

Students put all of their addition and subtraction skills together to solve equations. In this lesson, students put all of their addition and subtraction skills together to solve equations. Julia ...