Regardless of what your instructor or textbook teaches, you must follow the rules listed here to receive credit for answers that are required to be specified to a certain number of significant figures. If your instructor or textbook teaches significant figures differently than these rules, tell your instructor. Your instructor can turn off significant figure checking for assignments.
Operation | Rule | Examples |
|---|---|---|
Addition | Use the fewest number of decimal places specified in any of the operands. | 2.46 + 6.1743 = 8.63 |
Subtraction | Use the fewest number of decimal places specified in any of the operands. | 3.1415 - 2.2 = 0.9 |
Multiplication | Use the fewest number of significant figures specified in any of the operands. | 1530 × 4.0 = 6100 1530 × 4 = 6000 |
Division | Use the fewest number of significant figures specified in any of the operands. | 444 ÷ 4 = 100 444 ÷ 111 = 4.00 |
Exponentiation | Use the same number of significant figures as the base. | 210 = 1e3 2.00010 = 1024 |
Logarithms | Use the same number of decimal places in the result as the number of significant figures in the number you are taking the logarithm of. | log10(27) = 1.43 ln(0.026) = -3.65 |
Antilogarithms | Use the same number of significant figures in the result as the number of decimal places in the number you are taking the antilogarithm of. | 103.43 = 2700 e-3.65 = 0.026 |