WA.1.1. Core Content: Whole number relationships (Numbers, Operations) Students continue to work with whole numbers to quantify objects. They consider how numbers relate to one another. As they expand the set of numbers they work with, students start to develop critical concepts of ones and tens that introduce them to place value in our base ten number system. An understanding of how ones and tens relate to each other allows students to begin adding and subtracting two-digit numbers, where thinking of ten ones as one ten and vice versa is routine. Some students will be ready to work with numbers larger than those identified in the Expectations and should be given every opportunity to do so.
1.1.A. Count by ones forward and backward from 1 to 120, starting at any number, and count by twos, fives, and tens to 100.
1.1.E. Write, compare, and order numbers to 120.
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.C. Represent addition and subtraction on the number line.
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.