WA.1.2. Core Content: Addition and subtraction (Operations, Algebra) Students learn how to add and subtract, when to add and subtract, and how addition and subtraction relate to each other. Understanding that addition and subtraction undo each other is an important part of learning to use these operations efficiently and accurately. Students notice patterns involving addition and subtraction, and they work with other types of patterns as they learn to make generalizations about what they observe.
1.2.A. Connect physical and pictorial representations to addition and subtraction equations.
1.2.E. Add three or more one-digit numbers using the commutative and associative properties of addition.
1.2.F. Apply and explain strategies to compute addition facts and related subtraction facts for sums to 18.
1.2.G. Quickly recall addition facts and related subtraction facts for sums equal to 10.