2.NBT.7: Adding and Subtracting Within 1000

Visual Models to Use

• Base-Ten Blocks - Physical or virtual blocks representing hundreds (flat squares), tens (rods), and ones (small cubes) to model three-digit numbers and show regrouping when adding or subtracting.
• Place Value Chart - A chart with columns for hundreds, tens, and ones that helps your child organize digits by place value when adding and subtracting three-digit numbers.
• Number Line - A line showing numbers in sequence that helps visualize addition and subtraction with larger numbers, especially useful for counting up or counting back strategies.
• Expanded Form Drawings - Breaking numbers into expanded form (e.g., 357 = 300 + 50 + 7) to add or subtract by place value, often shown with boxes or circles around each place value.

Everyday Activities

1. Bank Balance Game

Create a pretend bank account with a three-digit balance. Have your child add deposits and subtract withdrawals, tracking the balance using place value strategies.

2. Shopping Budget

Give your child a budget of $500 or $800 and catalogs or online stores to "shop" from. Have them subtract the cost of items from their budget, showing their work.

3. Distance Tracker

On a road trip or using a map, track distances between cities that are within 1000 miles/kilometers. Have your child add distances for multi-city trips or find differences between routes.

4. Collection Counter

If your child has a collection (cards, toys, etc.), have them count and organize it by hundreds, tens, and ones. Then add or remove items and recalculate the total.

Strategies When Your Child Struggles

1. Use Base-Ten Blocks

When your child struggles with three-digit addition or subtraction, use physical or virtual base-ten blocks to represent the numbers and show the regrouping process.

2. Break It Down by Place Value

Help your child work with one place value at a time: first hundreds, then tens, then ones. For example, 325 + 246 becomes (300 + 200) + (20 + 40) + (5 + 6).

3. Draw Place Value Charts

Have your child draw a place value chart with columns for hundreds, tens, and ones to organize the digits when adding or subtracting.

4. Practice Regrouping Separately

If regrouping (carrying or borrowing) is challenging, practice just that skill with simpler numbers before tackling full three-digit problems.

5-Minute Practice Activities

1. Three-Digit Addition Race

Give your child two three-digit numbers to add (like 325 + 246). Have them solve it using place value strategies and explain their thinking.

2. Subtraction Challenge

Create subtraction problems with three-digit numbers (like 752 - 368). Have your child use drawings or base-ten blocks to solve them.

3. Missing Number Puzzles

Create equations with missing numbers like 423 + ___ = 671 or ___ - 285 = 412 for your child to solve using place value strategies.

4. Estimation First

Before solving a three-digit addition or subtraction problem exactly, have your child estimate the answer by rounding to the nearest hundred.

Mid-Year Expectations

By the middle of second grade, your child should be able to:

• Add and subtract within 1000 using concrete models or drawings
• Understand the concept of regrouping (carrying and borrowing) with three-digit numbers
• Explain their addition and subtraction strategies using place value language
• Solve problems with some guidance and support

End-of-Year Expectations

By the end of second grade, your child should be able to:

• Fluently add and subtract within 1000 using concrete models, drawings, or place value strategies
• Understand and apply regrouping across multiple place values (ones to tens, tens to hundreds)
• Explain why their strategies work using place value understanding
• Solve three-digit addition and subtraction problems independently

Mastery Signs

Your child has mastered this standard when they can:

• Add and subtract three-digit numbers accurately using appropriate strategies
• Regroup correctly when necessary in both addition and subtraction
• Explain their thinking process using place value language
• Apply these skills to solve real-world problems with three-digit numbers
• Check the reasonableness of their answers

Below Grade Level

Practice problems focusing on adding and subtracting two-digit numbers with regrouping, building the foundation for three-digit operations.

Download Practice Worksheet

At Grade Level

Standard practice with adding and subtracting three-digit numbers using concrete models or drawings and place value strategies.

Download Grade Level Worksheet

Above Grade Level

Challenging problems involving multi-step word problems requiring addition and subtraction within 1000 and mental math strategies with three-digit numbers.

Download Challenge Worksheet