Column Addition with Carried Tens

Rememb­er when we do column addition, we add the digits in the ones place (ones column) and then add the digits in the tens place (tens column).

But what happens when you're trying to solve a problem like this one?

34

+ 29

When you add the digits in the ones place, the sum (answer) equals 13. But there isn't enough room to write two digits at the bottom of the ones place. We only have room to write the ones digit, 3.

That means we must carry, or regroup, the tens digit. When we carry, we write the digit above the place value to the left. So we would write 1 above the tens place.

1

34

+ 29

3

Now we add the digits in the tens place, including the 1 that we just carried. What's 1 + 3 + 2? It's 6. We write 6 in the tens place. The answer to the problem is 63.

1

34

+ 29

63

We sometimes have to carry with three-digit numbers, too. Look at this problem:

462

+ 375

In this problem, 2 + 5 equals 7, so we don't need to carry. But when we get to the tens place, we have 6 + 7, which equals 13. So we write the ones digit, 3, in the tens place, and we carry the 1 to the top of the hundreds place (hundreds column). Then we add the digits in the hundreds place, including the 1 that we carried. Then we have 1 + 4 + 3 = 8.

1

462

+ 375