Standard
Apply properties of operations as strategies to add and subtract.<span class='footnote'>Students need not use formal terms for these properties.</span> <span class='clarification'>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.)</span>