CCSS.Math.Content.1.OA.D
The standard
Work with addition and subtraction equations.
Common Core State Standards for Mathematics
What this standard means
Students need to read, write, and make sense of number sentences with addition and subtraction. They should understand the equal sign as “the same amount as,” not as “the answer comes next.” They also need to decide if equations are true or false and find missing numbers in simple equations.
Mastery looks like a student explaining why 7 = 4 + 3 is true, solving 8 + ? = 11, and spotting that 5 + 2 = 6 is false. Common trouble spots are reversed equations, missing numbers in the first position, and treating the equal sign like a signal to calculate.
Ways to teach it
- Hands-on activity: Use two-color counters and balance mats to build equations like 6 + 2 = 8 and 8 = 6 + 2.
- Prompt: Ask students to explain, “Is 4 + 3 = 5 + 2 true or false? How do you know?”
- Quick assessment: Give four equations with one missing number, such as ? + 3 = 9, and have students solve on whiteboards.
- Real-world connection: Use classroom supplies to write equations, such as 5 pencils plus 2 pencils equals 7 pencils.
Plan a lesson for CCSS.Math.Content.1.OA.D
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Related standards
- CCSS.Math.Content.1.OA.B
Understand and apply properties of operations and the relationship between addition and subtraction.
- CCSS.Math.Content.2.OA.A
Represent and solve problems involving addition and subtraction.
- CCSS.Math.Content.1.OA.A
Represent and solve problems involving addition and subtraction.
- 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.