MathematicsClass 8Exponents and Powers

Standard Form of Numbers

Expressing very large or very small numbers compactly using scientific notation with powers of ten.

Class 8 · MathematicsCBSE & ICSE SOF IMO

Definition

The standard form of a number, also known as scientific notation, expresses extremely large or extremely small numbers as a decimal number between 1 and 10 multiplied by a power of 10. This format standardizes numerical representation to make calculations and comparisons much easier. Every non-zero number can be written in the form k \times 10^n, where 1 \le |k| < 10 and n is an integer.

Key formula

k \times 10^n

Worked examples

1

Express 85,000 in standard form by moving the decimal 4 places to the left, resulting in 8.5 \times 10^4.

2

Write 0.000042 in standard form by moving the decimal 5 places to the right, yielding 4.2 \times 10^{-5}.

3

Convert 300,000,000 to standard form to get 3 \times 10^8.

Common mistakes

  • Placing a number greater than 10 or less than 1 as the coefficient, such as writing 85 \times 10^3 instead of 8.5 \times 10^4.
  • Confusing the sign of the exponent of 10, using a positive exponent for small decimal numbers or a negative exponent for large whole numbers.
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