How to Teach Double-Digit Addition (With and Without Regrouping)

Quick answer

To teach double-digit addition, have your child add the ones column first, then the tens column. When a column adds up to more than 9, they regroup: write the ones digit and carry the extra ten to the next column. Start with problems that don’t need regrouping (like 24 + 13), then move on to ones that do (like 28 + 16). Most kids learn this in 1st and 2nd grade.

Double-digit addition is the first time kids add numbers in columns, and it’s a real jump from adding small numbers in their heads. The routine itself is short and it repeats every time, which is what makes it teachable. Below is how to walk through it, starting without regrouping and then adding it in, along with the mistakes to watch for and a free worksheet.

What is double-digit addition?

Double-digit addition (also called two-digit addition) means adding numbers that each have two digits, a tens place and a ones place, such as 34 + 28. Instead of counting one by one, children learn to line the numbers up by place value and add each column.

This skill sits squarely in early elementary math and maps to Common Core State Standards:

1st grade (1.NBT.C.4): add a two-digit number and a one-digit number, and add a two-digit number and a multiple of ten.
2nd grade (2.NBT.B.5): fluently add two two-digit numbers within 100 using place-value strategies.

Start here: double-digit addition without regrouping

Always begin with problems where no column adds up past 9. This lets your child learn the routine without the extra step of carrying.

Take 24 + 13:

Stack the numbers so the tens line up over tens and ones over ones.
Add the ones column first: 4 + 3 = 7. Write 7 in the ones place.
Add the tens column: 2 + 1 = 3. Write 3 in the tens place.
Read the answer: 37.

How to teach double-digit addition with regrouping (carrying)

Regrouping is the step that trips kids up, so slow down here. Regrouping happens when a column adds up to 10 or more. Since each place can only hold a single digit, the extra ten has to move to the next column.

Take 28 + 16:

Add the ones column: 8 + 6 = 14. That’s more than 9, so we regroup.
Keep the ones, carry the ten: 14 is 1 ten and 4 ones. Write the 4 in the ones place and carry the 1 above the tens column.
Add the tens column, including the carried ten: 1 + 2 + 1 = 4. Write 4 in the tens place.
Read the answer: 44.

The idea that makes this click is “10 ones become 1 ten.” When you have 10 or more ones, you bundle ten of them together and that bundle moves to where tens live.

The 3 mistakes kids make most (and how to fix them)

Fun ways to practice double-digit addition at home

Practice sticks when it’s short and real. A few ideas:

Store receipts: add two prices and check against the total.
Dice or cards: flip two cards to build each two-digit number, then race to add them.
Score-keeping: add up points in a board game or backyard game.
Daily 5: five problems a day beats twenty once a week, because steady repetition is what builds fluency.

Keep sessions to five or ten minutes, and when your child gets one wrong, give a hint and let them try again before you show the answer. That second try is where the learning happens.

Free Double-Digit Addition Worksheet

20 problems (with & without regrouping) + answer key · no email required

Open & print

How to know your child is ready to move on

Your child has mastered double-digit addition when they can:

Add two two-digit numbers without regrouping, quickly and accurately.
Recognize when a column needs regrouping and carry correctly.
Explain why they carry (“10 ones make 1 ten”).
Solve simple word problems that use double-digit addition.

When those feel solid, the natural next steps are double-digit subtraction with regrouping and three-digit addition, which use the very same column routine.

The easiest way to give your child practice

For most parents, the hardest part of teaching double-digit addition isn’t the math. It’s coming up with enough of the right problems and keeping your child willing to do them. That’s where Octolearn helps: describe the skill (“double-digit addition with regrouping”), and it builds a grade-matched practice set with read-aloud support, a hint and a second try on every question, and stars that keep kids coming back.

Frequently asked questions

What grade is double-digit addition taught in?

Double-digit addition usually begins in 1st grade with adding a two-digit number and a one-digit number (Common Core standard 1.NBT.C.4), and is mastered in 2nd grade, where children add two two-digit numbers fluently within 100 (standard 2.NBT.B.5). Many kids are ready to start once they can confidently add within 20 and understand tens and ones.

What is regrouping in addition?

Regrouping (also called carrying) is what you do when a column adds up to 10 or more. Because each place can only hold one digit, you keep the ones digit in that column and carry the ten over to the next column on the left. For example, in 28 + 16 the ones make 8 + 6 = 14, so you write the 4 and carry the 1 ten.

How do I explain carrying the 1 to my child?

Use ten as a bundle. When the ones column makes 10 or more, explain that 10 ones become 1 ten, so that new ten has to move over to the tens column where tens live. Base-ten blocks or ten bundled straws make this concrete: the child physically trades 10 ones for 1 ten and slides it to the next column.

Should I teach addition with or without regrouping first?

Teach without regrouping first. Starting with problems like 24 + 13, where no column goes past 9, lets your child learn the column routine (add the ones, then the tens) without the extra step of carrying. Once that feels automatic, introduce regrouping.

What is the best way to practice double-digit addition at home?

Mix short, daily practice with real-life math: adding prices, scores, or ages. Use base-ten blocks for kids who need it concrete, keep sessions to five or ten problems, and give a hint before the answer so a mistake turns into a lesson. Apps like Octolearn generate grade-matched sets with read-aloud support so kids can practice on their own.