Addition Guide

Regrouping in Addition

A Step-by-Step Visual Guide for Kids

Most regrouping errors happen because children learn the steps without understanding why carrying works. This guide shows both — so the procedure actually makes sense.

Ask this question first:

"Do the ones add up to 10 or more?"

If YES → Regroup (carry the ten). If NO → Write the number directly.

How to Regroup — Step by Step

Let's use 27 + 35 as our example

27 + 35 = ?
Start with the problem

We need to add 27 and 35. Write them vertically, lining up the ones and tens.

Step 1: Add the ones column
7 + 5 = 12
⚫⚫⚫⚫⚫ ⚫⚫⚫⚫⚫ ⚫⚫

7 ones + 5 ones = 12 ones. But 12 ones is more than 9 — we need to regroup.

Step 2: Regroup 12 ones
12 ones = 1 ten + 2 ones
🔟 + ⚫⚫

Write the 2 in the ones place. Carry the 1 ten to the tens column.

Step 3: Add the tens column
1 + 2 + 3 = 6
🔟🔟🔟🔟🔟🔟

Add the carried 1 ten + 2 tens + 3 tens = 6 tens.

Step 4: Write the answer
6 tens + 2 ones = 62
🔟🔟🔟🔟🔟🔟 + ⚫⚫

The answer is 62. The carried ten made the tens column larger.

27 + 35 = 62 ✓
We have the answer

Regrouping works because 10 ones make 1 ten — the value stays the same.

Why Regrouping Works

Regrouping works because 10 ones make 1 ten. The value stays the same — you're just changing how the number is written.

27 + 35 = (2 tens + 7 ones) + (3 tens + 5 ones)
= 2 tens + 3 tens + 7 ones + 5 ones
= 5 tens + 12 ones
= 5 tens + (1 ten + 2 ones)
= 6 tens + 2 ones
= 62 ✓

Visual reminder: 10 ones (⚫⚫⚫⚫⚫ ⚫⚫⚫⚫⚫) regroup into 1 ten (🔟).

Try These Examples

Follow the same steps: add ones, regroup if needed, add tens

38 + 26
8 + 6 = 14 → carry 1
1 + 3 + 2 = 6
= 64
47 + 38
7 + 8 = 15 → carry 1
1 + 4 + 3 = 8
= 85
56 + 29
6 + 9 = 15 → carry 1
1 + 5 + 2 = 8
= 85
64 + 27
4 + 7 = 11 → carry 1
1 + 6 + 2 = 9
= 91
79 + 18
9 + 8 = 17 → carry 1
1 + 7 + 1 = 9
= 97
85 + 46
5 + 6 = 11 → carry 1
1 + 8 + 4 = 13
= 131

Common Mistakes (And How to Fix Them)

Forgetting to add the carried number
Write the small carried number above the tens column. Say aloud: "1 ten + 2 tens + 3 tens = 6 tens."
Regrouping when the sum is less than 10
Only regroup when the ones sum is 10 or more. If the sum is 9 or less, write it directly.
Writing the carried number in the answer
The carried number is added to the tens column — it is not written as part of the ones answer.

Understanding place value is the key to mastering regrouping.

Number Sense Foundations

GRADES K–2

$57

Regrouping is where addition gets tricky for most kids — and the reason is almost always that place value wasn't fully solid first. This course builds genuine number sense, starting with place value, then moving through composing and decomposing numbers, addition and subtraction concepts, and the mental math strategies that make regrouping feel natural rather than like a magic trick. Every lesson tells you exactly what to say, what to watch for, and what to do when a child is stuck.

Get Number Sense Foundations on Gumroad →

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