CCSS.Math.Content.2.OA.A

CCSS.Math.Content.2.OA.A is a cluster heading. These are the individual standards under it.

• CCSS.Math.Content.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,...

01

What Students Need to Do

Students decide whether addition, subtraction, or both will solve a story problem. They represent the situation with objects, drawings, and equations, then find and explain the unknown amount.

02

What Mastery Looks Like

Students solve one-step and two-step problems within 100 and explain why they added or subtracted. They use drawings, objects, or equations and can find an unknown in any position.

03

Common Misconceptions

Students may choose an operation from a keyword without thinking about the situation. They may also place the unknown only after the equals sign or subtract the larger number from the smaller number automatically.

04

How to Assess It

Give this exit ticket: “Mia had some stickers, gave away 17, and has 26 left. How many did she start with?” Ask for a drawing, equation, and answer.

1. 01

   Give pairs counters and cups to model “45 apples, 18 sold,” then have them write and solve a matching equation.

2. 02

   Ask, “How can subtraction solve a problem when the starting amount is missing?” Have students compare two solution methods.

3. 03

   Play a card sort where students match story problems to equations, including equations with the unknown in different positions.

4. 04

   Set up a classroom supply shop where students calculate totals, amounts left, and missing starting quantities using prices under 100.

• CCSS.Math.Content.1.OA.D

  Work with addition and subtraction equations.

• CCSS.Math.Content.3.OA.A

  Represent and solve problems involving multiplication and division.

• CCSS.Math.Content.1.OA.A

  The 1st Grade version of this standard.

• CCSS.Math.Content.K.OA.A.2

  Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.