Significant figures

Definition

Significant figures are the digits in a number that carry meaningful information about its precision. They include all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion.

5 Must Know Facts For Your Next Test

1. Leading zeros are not considered significant.
2. When multiplying or dividing, the number of significant figures in the result is determined by the original number with the fewest significant figures.
3. When adding or subtracting, the result should have as many decimal places as the original number with the least decimal places.
4. Exact numbers, like counted items or defined constants, have an infinite number of significant figures.
5. Scientific notation helps to clearly indicate which digits are significant.

Review Questions

• What is the rule for determining significant figures when multiplying two numbers?
• How do you determine the number of significant figures in 0.00450?
• Why are exact numbers considered to have an infinite number of significant figures?

Related terms

Accuracy:

The closeness of a measured value to a standard or known value.

Precision:

The closeness of two or more measurements to each other.

Scientific Notation:

A method of expressing very large or very small numbers by using powers of ten.