Adding and subtracting whole numbers

Column addition

Numbers can be added together using the column method which involves writing one number underneath the other.

Example

What is 343 + 315?

Units column, 3+5=8

Start from the units column: 3 + 5 = 8

curriculum-key-fact
If the two numbers in a place value column add up to a number greater than 9, you must carry a digit.

Example

What is 343 + 329?

Units column, 3+9=12

Start from the units column: 3 + 9 = 12, place a 2 in the units column and carry 10 to the tens column by placing a 1

Question

Using column addition, work out the value of 427 + 363.

Example of column addition (427 + 363)

The answer is 790.

Column subtraction

Numbers can also be subtracted using the column method.

Example

What is 548 - 125?

Units column, 8-5=3

Start from the units column: 8 - 5 = 3

curriculum-key-fact
When subtracting two numbers in a place value column, if the second number is larger than the first it cannot be subtracted. You need to exchange a digit from a higher column.
Units column, 3-7

Start from the units column: 3 - 7

Question

Using column subtraction, work out the value of 427 - 363.

Example of column subtraction (427 - 363)

The answer is 64.