GCSE MATHS PRACTICE
GCSE Standard Form Questions
For a positive number, standard form is a × 10ⁿ, where 1 ≤ a < 10 and n is an integer. Move the decimal point to make a number between 1 and 10, then use a power of ten to keep the original value. Positive powers represent large numbers; negative powers represent small decimals. Try the example and four questions below.
Updated 8 October 2026
Worked example
Write 0.00072 in standard form.
- Move the decimal point four places to the right to obtain 7.2.
- Moving right has made the number 10⁴ times larger, so multiply by 10⁻⁴ to recover the original value.
- Check that 7.2 is at least 1 and less than 10.
Answer: 7.2 × 10⁻⁴
Practice questions
- 1
Write 580 000 in standard form.
- 2
Write 0.000093 in standard form.
- 3
Write 6.4 × 10³ as an ordinary number.
- 4
A sensor records 3 × 10⁴ readings each hour for 4 × 10² hours. How many readings is this? Give your answer in standard form.
Show answers
- 1. 5.8 × 10⁵
- 2. 9.3 × 10⁻⁵
- 3. 6400
- 4. 1.2 × 10⁷ readings
Common mistakes
- Using a first number outside the range — It must be at least 1 and less than 10.
- Reversing the sign of the power — Small positive decimals below 1 need negative powers.
- Leaving a calculation unfinished — Rewrite a result such as 12 × 10⁶ so its first number is less than 10.