Lesson 2 of 12

➕ Addition with Regrouping

🎯 3rd Grade ⏱ ~25 minutes 🟢 Beginner

What You'll Learn

  • How to add two numbers using regrouping (carrying)
  • When and why we carry a ten into the next column
  • Mental math strategies for fast addition

What Is Regrouping?

When you add two numbers and the ones column adds up to 10 or more, you regroup — you carry a group of 10 into the tens column.

Example: 47 + 35

  1. Ones: 7 + 5 = 12. Write the 2, carry the 1 (one ten) to the tens column.
  2. Tens: 4 + 3 + 1 (carried) = 8.
  3. Answer: 82
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Think in Groups of 10

Regrouping is just recognizing that 10 ones = 1 ten, and 10 tens = 1 hundred. You are not inventing a new number — you are just writing it in a smarter way.

Mental Math Strategies

  • Round and adjust: 48 + 37 → 50 + 37 = 87, then subtract 2 → 85
  • Make a ten: 37 + 25 → 37 + 3 = 40, then + 22 = 62
  • Break apart: 63 + 28 → 63 + 20 = 83, then + 8 = 91
Quick Check

1. What do you do when the ones column adds up to more than 9?

AIgnore the extra
BWrite both digits in the ones place
CCarry a ten to the tens column

2. 47 + 36 = ?

A73
B83
C84

3. Which strategy makes 58 + 22 easiest?

AGuess
B58 + 22: add 2 to make 60, then add 20 = 80
CSubtract instead
← Place ValueSubtraction →