How to Divide by 1000

When you need to divide a number by $1000$ , there’s a great trick you can use!

Rule

When you divide a number by $1000$ , you move the point in the number three places to the left.

There are three special cases you’ll come across:

1.: If the number is not a decimal number, remember that there is always an invisible point behind the last digit. Then you can move that point three places to the left.
2.: If the number ends in a $0$ , moving the point past that makes the $0$ disappear.
3.: If you have to move the point past all the digits of the number, you get empty places at the start of the number that you fill up with $0$ .

You’ll use the rule in the box below a lot moving forward. Make sure you understand what it says. Below the box there will be some examples.

Rule

Dividing by $1000$ is the same as multiplying by $0.001$ :

1 \div 1000 = \frac{1}{1000} = 0.001

The trick of moving the decimal point when dividing by 1000, is similar to a trick you can use when multiplying by 1000.

Example 1

Dividing by 1000

a)
$61 \div 1000 = 0.061$

b)
$763.4 \div 1000 = 0.7634$

c)
$20 \div 1000 = 0.020 = 0.02$

d)
$0.4 \div 1000 = 0.0004$

Example 2

Multiplying by $0.001$

a)
$\begin{array}{l} 61 \cdot 0.001 & = 61 \div 1000 \\ = 0.061 \end{array}$

$61 \cdot 0.001 = 61 \div 1000 = 0.061$

b)
$763.4 \cdot 0.001 = 0.7634$

c)
$\begin{array}{l} 20 \cdot 0.001 & = 20 \div 1000 \\ = 0.02 \end{array}$

$20 \cdot 0.001 = 20 \div 1000 = 0.02$

d)
$\begin{array}{l} 0.4 \cdot 0.001 & = 0.4 \div 1000 \\ = 0.0004 \end{array}$

$0.4 \cdot 0.001 = 0.4 \div 1000 = 0.0004$