Georgia 2.NR.2.3
The Standard
Solve problems involving the addition and subtraction of two-digit numbers using part-whole strategies.
Georgia's K-12 Mathematics Standards · Apply multiple part-whole strategies, properties of operations and place value understanding to solve real-life, mathematical problems involving addition and subtraction within 1,000.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students break two-digit numbers into tens, ones, or other helpful parts. They add or subtract the parts, recombine them, and explain their steps.
What Mastery Looks Like
- Students accurately solve two-digit addition and subtraction problems by splitting numbers into tens and ones or other useful parts. They record their steps and explain why their method works.
Common Misconceptions
- Students may combine tens with ones instead of matching place values. In subtraction, they may always subtract the smaller digit from the larger digit or regroup without adjusting the tens.
How to Assess It
- Exit ticket: Solve 58 + 27 and 74 - 38. Show how you split the numbers into parts, then recombine them.
Lesson moves
Ways to Teach It
Give pairs base-ten blocks to model 46 + 37 and 83 - 29, then record each model with equations.
Ask students to compare two solutions for 54 + 28 and explain which number parts made each method efficient.
Play a card game where students draw two two-digit numbers, choose addition or subtraction, and solve by decomposing both numbers.
Use a classroom store price list and have students find total costs and change using tens-and-ones drawings or equations.
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Printable 2.NR.2.3 Worksheet
A ready-to-print activity worksheet aligned to 2.NR.2.3, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- 3.PAR.2
Use part-whole strategies to represent and solve real-life problems involving addition and subtraction with whole numbers up to 10,000.
- 3.PAR.3
Use part-whole strategies to solve real-life, mathematical problems involving multiplication and division with whole numbers within 100.
- 1.NR.5.1
Use a variety of strategies to solve applicable, mathematical addition and subtraction problems with one- and two-digit whole numbers.
- 4.NR.2
Using part-whole strategies, solve problems involving addition and subtraction through the hundred-thousands place, as well as multiplication and division of mu...
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