Revision Notes

1.5.1 Standard Form - Basics

What is standard form?

  • Standard Form (sometimes called Standard Index Form) is a way of writing very big and very small numbers using powers of 10

Why do we use standard form?

  • Writing big (and small) numbers in Standard Form allows us to:
    • write them more neatly
    • compare them more easily
    • and it makes things easier when doing calculations

How do we use standard form?

  • Using Standard Form numbers are always written in the form:
    a × 10n
  • The rules:
    • 1 ≤ a < 10 so there is one non-zero digit before the decimal point
    • n > 0 for LARGE numbers – how many times a is multiplied by 10
    • n < 0 for SMALL numbers – how many times a is divided by 10
    • Do calculations on a calculator (if allowed)
      Otherwise follow normal rules (including indices) but adjust answer to fit Standard Form (move decimal point and change n

Worked Example

Standard Form Ex, IGCSE & GCSE Maths revision notes


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