Standard form (GCSE)
a × 10n with 1 ≤ a < 10. Both tiers; large + small.
Standard form is a GCSE staple, especially for science cross-overs. Calculators show 'EE' or '×10x' buttons; mode > Sci sets fixed standard-form display.
Worked examples
3,400,000 = 3.4 × 106.
0.0000045 = 4.5 × 10−6.
(3 × 105) × (4 × 103) = 12 × 108 = 1.2 × 109.
Frequently asked questions
Without calculator?
Year 10/11 work both ways. Multiplying: multiply the a values, add the indices, then adjust if a is ≥ 10.
Why a between 1 and 10?
Uniqueness — 3.4 × 106 is the only correct standard-form representation of 3,400,000.