Column addition is very useful if you need to add two or more numbers together and you are unable to use mental addition
24 + 35
To do column addition correctly it is important that you understand place value and put each number in the correct column
First you need to put the numbers one on top of the other so that the tens are above the tens and the units are above the units.
Add the two numbers in the units column first. 4 + 5 = 9 so the number 9 is placed below the units.
Next add the two numbers in the tens column. 2 + 3 = 5 so the number 5 is placed below the tens.
The answer is 5 tens and 9 units or 59
If the numbers in any of the columns add up to more than 9 then we have to carry a number to the next column
In this example, when you add the numbers in the units column together the answer is 13.
13 is a higher number than 9 and is made up of 1 ten and 3 units. So we put the 3 units below the units column and place the 1 ten in the tens column below the answer line.
When you add the tens column you have to remember add in the 1 ten that has been carried over.
Sometimes the carry figure is placed at the top of the column as shown in the diagram below
The same method is used to add together bigger numbers
The numbers in the units column are added together first
9 + 8 = 17 so the 7 is placed in the units column and the 1 is carried over to the next column and placed at the top.
Next the numbers in the tens column are added together
1 + 4 + 6 = 11 so a 1 is placed in the tens column and the other 1 is carried over to the hundreds column
Finally the numbers in the hundreds column are added together
1 + 2 + 1 = 4 so a 4 is placed in the hundreds column
The answer to the sum 249 + 168 = 417
Harvard Reference for this page:
Heather Y Wheeler. (2015). Column Addition. Available: http://www.tiffanymacbeth.com/Maths/column_addition.htm. Last accessed