What does 'carrying' actually mean?

When a column adds up to 10 or more, you have made a full group of ten (or hundred). That group belongs in the next place to the left, so you 'carry' it there. It is also called regrouping.

Where do I write the carried digit?

Write a small 1 above the next column to the left, then include it when you add that column. Some people write it at the bottom instead — either is fine as long as you remember to add it.

Column Addition with Carrying | Math

What is column addition?

Column addition is a neat way to add numbers by stacking them on top of each other and adding one column at a time. It works for any size of number, which makes it more powerful than adding in your head.

The secret to column addition is place value. If you are unsure about ones, tens and hundreds, look at Place Value to Thousands first.

Setting up: line up the place values

Before you add anything, you must line up the digits so the same places sit in the same column:

ones under ones
tens under tens
hundreds under hundreds

If the columns are not lined up, you will add the wrong things together. Write the numbers stacked, with a line underneath for the answer.

  47
+ 38
----

The rule for carrying

You can only fit one digit in each column. But what if a column adds up to 10 or more? Then you have made a whole group of ten, and a group of ten belongs in the next column to the left.

So the rule is:

If a column total is 10 or more, write the ones digit in that column and carry the tens digit into the next column.

This is sometimes called regrouping because you are regrouping ten ones into one ten.

Worked example 1: two-digit numbers

Work out 47 + 38.

Ones column: 7 + 8 = 15. That is 1 ten and 5 ones. Write 5 in the ones place and carry 1 to the tens column.
Tens column: 4 + 3 = 7, then add the carried 1 → 7 + 1 = 8. Write 8.
Read the answer: 85.

Why it works: 47 + 38 really means (40 + 7) + (30 + 8). The ones gave us 15, which is one ten and five ones. We slid that extra ten over to join the other tens. That is exactly what carrying does.

Worked example 2: three-digit numbers with two carries

Work out 156 + 275.

Ones column: 6 + 5 = 11. Write 1, carry 1 to the tens.
Tens column: 5 + 7 = 12, add the carried 1 → 13. Write 3, carry 1 to the hundreds.
Hundreds column: 1 + 2 = 3, add the carried 1 → 4. Write 4.
Read the answer: 431.

Notice we carried twice in this sum. That is completely normal — just take one column at a time.

Worked example 3: numbers of different lengths

Work out 1,485 + 96.

Line up from the right so the ones match. The shorter number simply has empty spaces (or zeros) on the left.

Ones: 5 + 6 = 11. Write 1, carry 1.
Tens: 8 + 9 = 17, add carried 1 → 18. Write 8, carry 1.
Hundreds: 4 + 0 = 4, add carried 1 → 5. Write 5.
Thousands: 1 + 0 = 1. Write 1.
Read the answer: 1,581.

The empty places in 96 act like zeros, so 4 + (nothing) = 4.

Checking your answer

A quick estimate tells you if your answer is sensible.

Sum	Rounded estimate	Exact answer	Sensible?
47 + 38	50 + 40 = 90	85	Yes, close to 90
156 + 275	160 + 280 = 440	431	Yes, close to 440
1,485 + 96	1,500 + 100 = 1,600	1,581	Yes, close to 1,600

If your exact answer is wildly different from the estimate, you have probably forgotten a carry — go back and check.

Try it yourself

Set these out in columns and add, carrying when needed.

58 + 26 (Answer: 84)
367 + 248 (Answer: 615)
749 + 158 (Answer: 907)

For the last one, watch the tens column: 4 + 5 + carried 1 = 10, so write 0 and carry 1 again.

Great job!

You can now add big numbers neatly using column addition, and you understand why carrying moves a ten to the next place. This is one of the most useful skills in all of maths.

Next, learn the opposite operation in Column Subtraction with Borrowing, or build quick number sense with Mental Math Strategies.

Column Addition with Carrying

Key takeaways