How to Teach Addition With Carrying (Regrouping)

Carrying — also called regrouping — is the first place many children get stuck in math. This guide breaks it down into small, teachable steps that work at the kitchen table or in the classroom.

Carrying (the word most US classrooms now call regrouping) happens whenever the digits in one column add up to more than 9. Instead of writing a two-digit number in a single column, the child writes one digit and "carries" the other to the next column. It sounds simple to adults, but for a 7- or 8-year-old it is a genuine conceptual leap.

Make sure the basics are solid first

Before introducing carrying, a child should be comfortable with two things: addition facts up to 18 (for example, 8 + 5 = 13) and the idea of place value — that the "2" in 24 means two tens. If either of these is shaky, carrying will feel like magic rather than logic. Spend a few sessions on single-digit addition and on naming the tens and ones place before moving on.

Step 1: Start with concrete objects

Use something a child can physically group into tens: craft sticks bundled with rubber bands, base-ten blocks, or even coins. Show that when ten ones come together, they become a single "ten." This is exactly what carrying does on paper — it bundles ten ones into one ten and moves it to the next column.

Step 2: Line up the columns

Write a problem like 27 + 15 vertically, with the ones under the ones and the tens under the tens. Neat columns are not just tidy — they are the whole point. Many "carrying mistakes" are really alignment mistakes. Graph paper or a worksheet with built-in boxes keeps digits in the right place.

Step 3: Add the ones column first

In 27 + 15, the ones are 7 + 5 = 12. Say out loud: "Twelve is one ten and two ones. We write the 2 here in the ones place, and the 1 ten goes up to the top of the tens column." Physically write the small carried 1 above the tens. Naming the value ("one ten," not just "one") keeps the place-value meaning front and center.

Step 4: Add the tens column, including the carry

Now add 2 + 1 + the carried 1 = 4 tens. The answer is 42. Walk through several problems this way, always narrating the carry as "one ten" or "one hundred" depending on the column.

Common mistakes — and how to fix them

• Forgetting to add the carried number. The child adds 2 + 1 and gets 3 instead of 4. Fix: write the carry clearly and have them touch it as they add.
• Writing the whole two-digit sum in one column. They write 12 in the ones place. Fix: go back to bundling ten ones into one ten with physical objects.
• Misaligned digits. 27 + 5 becomes 77 because the 5 was placed under the 2. Fix: use boxed or grid worksheets.
• Carrying when it isn't needed. Over-applying the rule. Fix: mix problems with and without carrying so the child has to decide each time.

How much practice is enough?

Short, daily practice beats long, occasional sessions. Ten to fifteen minutes a day, five days a week, is plenty for most children. The key is variety within the skill: some problems that need carrying, some that don't, and a gradual move from two-digit to three-digit numbers. Because every generated worksheet is different, your child practices the skill rather than memorizing one page of answers.

Signs your child is ready to move on

When a child can solve two-digit carrying problems accurately and explain why they carried — "because 7 plus 5 is more than nine" — they are ready for three-digit addition and for carrying in more than one column. That same regrouping logic carries straight into subtraction with borrowing, so the time you invest here pays off twice.