GlossariesGCSE GlossariesGCSE Maths GlossaryStandard Form

Standard Form - GCSE Maths Definition

Reviewed by: Dan Finlay

Last updated

5 March 2025

What is standard form?

In GCSE maths, a number can be written in standard form by writing it in the form $a \times 10^{k}$ , where $1 \leq a < 10$ and $k$ is an integer.

The value of $a$ can be found by identifying the first non-zero digit in the original number and putting a decimal point after it.

The value of $k$ can be found by counting the number of times that you need to multiply (or divide) the value $a$ by 10 in order to get the original number. If the value of $a$ is the original number, then you do not need to multiply or divide it by 10 so $k$ will be zero. If the original number is greater than or equal to 10, then you need to multiply $a$ by a power of 10 so $k$ will be positive. If the original number is less than 1, then you need to divide $a$ by a power of 10 so $k$ will be negative.

Here are some examples:

Ordinary form	Standard form
$12000$	$1.2 \times 10^{4}$
$0.00561$	$5.61 \times 10^{- 3}$
$10$	$1 \times 10^{1}$
$5.7$	$5.7 \times 10^{0}$

Standard form is also known as scientific notation. Standard form is useful when writing really big numbers or numbers that are very close to zero. It is also very useful when comparing the size of two numbers.