MathIsimple
Unit 1 of 7

Multi-Digit Addition & Subtraction

Master three-digit addition and subtraction! Learn to align place values, regroup numbers, and solve real-world problems with confidence.

4 Lessons
16+ Activities
2-3 hours
Easy to Medium

What You'll Learn

Add three-digit numbers with and without regrouping

Subtract three-digit numbers with and without regrouping

Use place value understanding to align numbers correctly

Apply addition and subtraction to real-world problems

Use estimation to check if answers are reasonable

Develop fluency and confidence with three-digit operations

4 Comprehensive Lessons

Your Learning Journey

Lesson 1
Easy
30-35 min

Three-Digit Addition Without Regrouping

Learn to add three-digit numbers when no regrouping is needed. Master place value alignment and build foundational addition skills.

Topics

Place value alignment
Adding hundreds
Adding tens and ones
Vertical format

Skills

  • Align numbers by place value
  • Add in columns
Lesson 2
Medium
35-40 min

Three-Digit Addition With Regrouping

Master addition with regrouping! Learn when and how to 'carry' numbers when adding three-digit numbers.

Topics

Regrouping ones to tens
Regrouping tens to hundreds
Multiple regrouping steps
Money scenarios

Skills

  • When to regroup
  • Trade 10 ones for 1 ten
Lesson 3
Easy
30-35 min

Three-Digit Subtraction Without Regrouping

Learn to subtract three-digit numbers when no regrouping is needed. Build confidence with straightforward subtraction.

Topics

Place value subtraction
Subtracting by columns
Checking with addition
Real-world problems

Skills

  • Align for subtraction
  • Subtract each column
Lesson 4
Medium
35-40 min

Three-Digit Subtraction With Regrouping

Master subtraction with regrouping! Learn to 'borrow' from tens and hundreds when subtracting three-digit numbers.

Topics

Borrowing from tens
Borrowing from hundreds
Cascade borrowing
Estimation check

Skills

  • When to borrow
  • Break apart tens or hundreds

Practice Worksheets

Reinforce learning with worksheets!

Basic

Foundation

Start
Advanced

Challenge

Start

Learning Path: Easy to Challenging

1

Start Simple

Three-Digit Addition Without Regrouping

2

Add Complexity

Three-Digit Addition With Regrouping

3

Practice Transfer

Three-Digit Subtraction Without Regrouping

4

Master Challenge

Three-Digit Subtraction With Regrouping

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Ready to Master Multi-Digit Operations?

Start with Lesson 1 and progress through all four lessons to build strong addition and subtraction skills!

Begin Unit 1