# Operations & Algebraic Thinking - 2nd Grade Common Core Math

## 2.OA.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.

Addition Word Problems within 100

Subtraction Word Problems within 100

## 2.OA.2

Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.

Addition Sentences

Add Two Numbers

Add Three Numbers

Addition Word Problems within 20

Relate Addition and Subtraction

Count Back to Subtract

Subtract

Fact Families

Subtraction Word Problems within 20

## 2.OA.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.

Even and Odd Numbers

## 2.OA.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.