What is Exponential / Scientific Notation?
Scientific notation (also called exponential notation) is a way of expressing very large or very small numbers in a compact form. A number is written as the product of a coefficient (mantissa) between 1 and 10, and a power of 10. For example, 45,600 becomes 4.56 x 104.
The general form is: a x 10n, where 1 ≤ |a| < 10 and n is an integer.
Conversion Examples
Large Numbers
Move the decimal point left until only one digit remains before it.
Small Numbers
Move the decimal point right until the first nonzero digit is before it.
Negative Numbers
Apply the same rules, keeping the negative sign.
E-Notation
Computers use E-notation: mantissa followed by 'e' and the exponent.
Why Use Scientific Notation?
Scientific notation is essential in science, engineering, and computing because it makes extremely large or small numbers manageable. The speed of light (299,792,458 m/s) is more easily written as 2.998 x 108 m/s. The mass of an electron (0.000000000000000000000000000000911 kg) becomes 9.11 x 10-31 kg.
Key Terminology
- Mantissa (Coefficient): The number between 1 and 10 in scientific notation.
- Exponent: The power of 10 that indicates how many places to move the decimal.
- E-Notation: Computer-friendly format where 'e' separates mantissa and exponent.
- Significant Figures: The meaningful digits in the mantissa.
Tips for Converting
- Count decimal places moved to determine the exponent.
- Moving the decimal left gives a positive exponent (large numbers).
- Moving the decimal right gives a negative exponent (small numbers).
- The mantissa must be at least 1 but less than 10.
- When converting back, move the decimal in the opposite direction.