GCSE Math · Number · Fractions, decimals and percentages
Standard form
Writing and calculating with numbers in standard form
How it works
Standard form writes numbers as a × 10^n, where 1 ≤ a < 10 and n is an integer. Large numbers have a positive power of 10 and small numbers (less than 1) have a negative power. When multiplying or dividing standard form numbers, combine the powers of 10 and the coefficients separately, then convert back to standard form if needed.
The method
- 1.Move the decimal point until only one non-zero digit is before it
- 2.Count how many places the decimal point moved to find n
- 3.Use a positive power for numbers ≥ 1 and negative for numbers < 1
- 4.Write in the form a × 10^n
Worked example
Write 45,000 in standard form.
- Move decimal point 4 places: 4.5
- 45000 = 4.5 × 10^4
Worked example
Write 0.00032 in standard form.
- Move decimal point 4 places right: 3.2
- 0.00032 = 3.2 × 10^-4
Common mistakes
- Writing the coefficient outside the range 1 ≤ a < 10
- Using the wrong sign on the power of 10 for small numbers
- Forgetting to adjust the power of 10 after multiplying coefficients