CCSS.Math.Content.3.NBT.A.2
The standard
Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
Common Core State Standards for Mathematics · Number and Operations in Base Ten
What this standard means
Students need to add and subtract three-digit numbers accurately and efficiently. They should use place value, not just count on fingers or stack digits without meaning. They need to explain moves like breaking 456 into 400, 50, and 6, making a ten, regrouping, or checking subtraction with addition.
Mastery looks like flexible strategy use and correct answers within 1000. A student can solve 638 minus 275, show a method, and tell why it works. Common trouble spots are regrouping across zero, lining up place values, subtracting the smaller digit from the larger digit, and forgetting to check if an answer makes sense.
Ways to teach it
- Use base-ten blocks to model 432 plus 286, regroup ones and tens, then record the matching written steps.
- Ask students to solve 704 minus 368 two ways and write which method felt easier and why.
- Give four problems on an exit ticket, including one addition, one subtraction, one with zeros, and one check with the inverse operation.
- Have students total pretend classroom supply costs under $1000, then find the change from a $1000 budget.
Plan a lesson for CCSS.Math.Content.3.NBT.A.2
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Related standards
- CCSS.Math.Content.2.NBT.B.5
Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
- CCSS.Math.Content.6.NS.B.3
Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.
- CCSS.Math.Content.2.NBT.B.7
Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between a...
- CCSS.Math.Content.4.NBT.B.4
Fluently add and subtract multi-digit whole numbers using the standard algorithm.