Rounding to Significant Figures
Result
Understanding Significant Figures
Significant figures (also called significant digits) are the digits in a number that contribute to its precision. They indicate the reliability and accuracy of a measurement or calculation.
Rules for Counting Significant Figures:
- Non-zero digits are always significant
- Zeros between non-zero digits are significant
- Leading zeros (zeros to the left of the first non-zero digit) are NOT significant
- Trailing zeros in a decimal number are significant
- Trailing zeros in a whole number without a decimal point may or may not be significant
Examples:
| Number | Sig Figs | Why |
|---|---|---|
| 123 | 3 | All non-zero |
| 1.05 | 3 | Zero between non-zeros |
| 0.00456 | 3 | Leading zeros don't count |
| 4.500 | 4 | Trailing zeros after decimal |
Rounding Examples:
- To 2 sig figs: 1.234 → 1.2
- To 3 sig figs: 0.05678 → 0.0568
- To 1 sig fig: 456 → 500
- To 4 sig figs: 12345 → 12350
Scientific Context: Significant figures are crucial in science and engineering for expressing the precision of measurements and calculations. More significant figures indicate higher precision.