How it’s calculated
Scientific notation writes a number as a coefficient between 1 and 10 times a power of ten. Count how many places the decimal point moves: to the left gives a positive exponent, to the right a negative one. Engineering notation uses only powers that are multiples of 3, matching SI prefixes (kilo, mega, milli, micro…).
Example: the speed of light, 299,792,458 m/s. The point moves 8 places left, so it is 2.99792458 × 10⁸; to 3 significant figures, 3.00 × 10⁸. In engineering notation it is 299.792458 × 10⁶ (299.79 mega-meters per second). Going the other way, 6.02214076 × 10²³ = 602,214,076,000,000,000,000,000.
Frequently asked questions
How do I write 0.00045 in scientific notation?
Move the point 4 places right to get 4.5, so it is 4.5 × 10⁻⁴.
What does 1.5E-3 mean on a calculator?
E means "times ten to the power". 1.5E-3 = 1.5 × 10⁻³ = 0.0015.
Are trailing zeros significant?
In scientific notation, yes: 3.00 × 10⁸ has three significant figures, 3 × 10⁸ has one.
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Sources
- Prealgebra 2e, §10.5 Integer Exponents and Scientific Notation — OpenStax
- Chemistry 2e, Appendix B: Essential Mathematics — OpenStax
Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.
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