2.OA. Grade 2 - Operations and Algebraic Thinking

2.OA.A. Represent and solve problems involving addition and subtraction.

2.OA.A.1. Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.See Glossary, Table 1.

• A Pencil and a Sticker
• Saving Money 2

2.OA.B. Add and subtract within 20.

2.OA.B.2. Fluently add and subtract within 20 using mental strategies.See standard 1.OA.6 for a list of mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

• Building toward fluency
• Hitting The Target Number

2.OA.C. Work with equal groups of objects to gain foundations for multiplication.

• Delayed Gratification

2.OA.C.3. Determine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.

• Buttons odd and even
• Red and Blue Tiles

2.OA.C.4. Use addition to find the total number of objects arranged in rectangular arrays with up to 5 rows and up to 5 columns; write an equation to express the total as a sum of equal addends.

• Counting Dots in Arrays
• Partitioning a Rectangle into Unit Squares