How to Do Long Addition
What Is Long Addition? (Interactive Widget)
Use this interactive widget to see a stepbystep explanation of long addition.

This is a randomly generated longaddition sum.

Long Addition
Long addition is a method for adding numbers.
Long addition involves writing the numbers to be added one underneath another, so the digits are in columns. The numbers are added a column at a time.
Many numbers of any length (including decimals) can be added in this way.
How to Do Long Addition
StepbyStep:
1
Write the numbers you wish to add, one underneath the other.
2
Add up the numbers in the rightmost column.
3
Check if the answer from the previous Step is 9 or less:

If Yes, write the number below the column (between the lines) and move to Step 4.

If No, the answer will have two digits.
Write the digit on the right underneath the column (between the lines).
Write the digit on the left underneath the column to the left of the current column (below the two lines).
This is carrying. Move to Step 4.
4
Move to the column to the left. Add up the numbers in this column, including any numbers below the two lines.
5
Go to Step 3 and repeat until all columns have been added.
A Real Example of How to Do Long Addition
Doing long addition is easy.
Question
Add the numbers below.
StepbyStep:
1
Write the numbers you wish to add, one underneath the other.
2
Add up the numbers in the rightmost column.
7 + 4 = 11
3
Check if the answer from Step 2 is 9 or less:
No. 11 is not 9 or less.

If No, the answer will have two digits.

Write the digit on the right underneath the column (between the lines).

Write the digit on the left underneath the column to the left of the current column (below the two lines).
This is carrying. Move to Step 4.
4
Move to the column to the left.
Add up the numbers in this column, including any numbers below the two lines.
2 + 8 + 1 = 11
5
Go to Step 3 and repeat until all columns have been added.
3
1^{st} repeat
Check if the answer from the previous Step 4 is 9 or less:
No. 11 is not 9 or less.

If No, the answer will have two digits.

Write the digit on the right underneath the column (between the lines).

Write the digit on the left underneath the column to the left of the current column (below the two lines). This is carrying. Move to Step 4.
4
1^{st} repeat
Move to the column to the left.
Add up the numbers in this column, including any numbers below the two lines.
3 + 1 + 1 = 5
5
1^{st} repeat
Go to Step 3 and repeat until all columns have been added.
3
2^{nd} repeat
Check if the answer from the previous Step 4 is 9 or less:
Yes. 5 is 9 or less.

If Yes, write the number below the column (between the lines).
There are no more columns to the left. All columns have been added.
Answer:
The solution to 327 + 184 is 511.