Engineering notation is a version of scientific notation in which the exponent p in expressions of the form a×10^p is chosen to always be divisible by 3. Numbers of forms such as 12×10^(-6), 230×10^(-3), 340, and 4.5×10^3 therefore correspond to engineering notation, while numbers such as 12×10^(-2), 2×10^2, and 123×10^5 do not. 16 of the 20 SI prefixes (excluding centi-, deci-, deka-, and hecto-) correspond to engineering notation.

expanded notation | scientific notation | significant digits | SI prefixes