How_To_Be_Good_At_Math

84 CALCULATING •^ EXPANDED COLUMN ADDITION

Expanded

Column addition

To add together numbers that have more than two digits, we can use column

addition. There are two ways to do it. The method shown here is called expanded

column addition. The other method, column addition, is shown on pages 86-87.

385 + 157 =?

Let’s add 385 and 157 using expanded

column addition.

Start by writing the two numbers out

like this, with digits that have the

same place value lined up one above the

other. It might help you to label the place

values, but you don’t have to.

Now we’re going to add each

of the digits in the top row to the

digits that sit beneath them in the

bottom row, starting with the ones.

First, add 5 ones and 7 ones. The

answer is 12 ones. On a new line,

write 1 in the tens column and 2 in the

ones column.

Write the

numbers so

that the digits

with the same

place value are

lined up like this

Write the

answer below

the answer line

Start by adding

the ones together

385

157

H T O

H T O

385

+^157

H T O

385

+^157

12

When we do

expanded column

addition, it’s important

to line up the digits by

their place values.

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