Use doubles facts

Doubles facts describe additions with equal addends, such as $6+6=12$, and establish the relationship between a number and twice that number for sums through $10+10=20$. These facts support efficient reasoning with near doubles, such as finding $6+7$ by adjusting $6+6$ by one, and reinforce the commutative structure of addition; more extensive multiplication or generalized doubling is beyond this scope.