How_To_Be_Good_At_Math

114 CALCULATING •^ EXPANDED SHORT MULTIPLICATION

Expanded short

multiplication

When one of the numbers in a multiplication calculation has more than

one digit, it can help to write the numbers out in columns. There's more

than one way to do this. The method shown here, called expanded short

multiplication, is useful when you're multiplying a number with more than

one digit by a single-digit number.

Let’s multiply 423 by 8 using expanded

Short multiplication

Start by writing the two numbers out

like this, with digits that have the

same place values 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 multiply each

of the digits on the top row by the

number 8 on the bottom row, starting

with the ones.

First, multiply 3 ones by 8 ones. The

answer is 24 ones. Write 24 on the

first answer row.

423

8

Write the

numbers so

that the digits

with the same

place values are

lined up like this

H T O

×

Th

423

8

We're going to

multiply each

digit on the top

row by 8

H T O

×

Th

423

(^8) Write the answer
on a row below
H T O
×
Th
24
423 × 8 =?
114_115_Expanded_short_multiplication.indd 114 29/02/2016 14:11