Multiplying 2 and 3-digit numbers by a 1-digit number

In a nutshell

It is common to use written methods when multiplying three-digit numbers and trickier two-digit numbers by a one-digit number, however, mental methods are still very useful.

Written methods

Short multiplication is a common written method for multiplying two- and three-digit numbers by a one-digit number.

Short multiplication

Using columns to set out and calculate, short multiplication is a quick way to work out multiplication calculations.

PROCEDURE

1.

Set out the calculation:

Align the ones one below the other ones and write out the rest of the digits in columns.
Draw a line beneath and a multiplication symbol to the left.

2.

Multiply each digit of the two/three-digit number by the single digit from right to left.

3.

Below the line in the answer space, write the unit digit of each calculation and carry over into the next column if required.

Example

Work out $132\times4$ .

Set out the calculation.

Maths; Multiplication and division; KS2 Year 4; Multiplying 2 and 3-digit numbers by a 1-digit number

Multiply each digit of the two/three-digit number by the single digit from right to left.

$\begin{aligned}\\&2\times4=8\\&3\times4 = 12\\&1\times4=4\end{aligned}$ 

Place the $8$ in the ones column.

$2\times4=8$

Maths; Multiplication and division; KS2 Year 4; Multiplying 2 and 3-digit numbers by a 1-digit number

Place the $2$ in the tens column and carry the one.

Maths; Multiplication and division; KS2 Year 4; Multiplying 2 and 3-digit numbers by a 1-digit number

Add the carried $1$ and place $5$ in the final column.

Maths; Multiplication and division; KS2 Year 4; Multiplying 2 and 3-digit numbers by a 1-digit number

$132\times4=\underline{528}$

Note: Mental methods such as partitioning, breaking down and taking away from a round number can also be used for multiplication involving a three-digit number and a one-digit number.