Understand and apply properties of operations and the relationship between addition and subtraction
Apply properties of operations as strategies to add and subtract. Examples: If 8 + 3 = 11 is known, then 3 + 8 = 11 is also known. (Commutative property of addition.) To add 2 + 6 + 4, the second two numbers can be added to make a ten, so 2 + 6 + 4 = 2 + 10 = 12. (Associative property of addition.) (Students need not use formal terms for these properties.)
Related Lessons
Lesson 207
Warm up with a Mystery Math Mistake to add 9 and 5 using a double 10-frame and a decompose strategy. Use near-doubles to add with double 10-frames and a compensation strategy.
Lesson 202
Represent 10 using a number bond and 10-frame to help solve a Mystery Math Mistake. Use Notice and Wonder with [...]
Lesson 203
Represent 10 using a number bond and 10-frame with a missing addend. Use Notice and Wonder with a 10-frame, connecting [...]
