Theory
Rounding a physics answer to significant figures
In physics, you do not write an answer more precisely than the data allow.
Significant figures are the meaningful digits of a number. Leading zeros do not count; zeros between or after meaningful digits can count.
Keep the requested number of significant figures and look at the next digit to determine whether you round up.
- Read the number and number of digitsTake the number to be rounded and the requested number of significant figures from the problem.
- Determine the rounding positionCount significant figures from the first digit that is not zero.
- Round offRound based on the next digit.
Round 12,346 to 3 significant figures.
- Read the number and number of digitsNumber = 12,346. Number of significant figures = 3.
- Determine the rounding positionKeep 3 significant figures; the next digit determines the rounding.
- Round off12,346 rounded to 3 significant figures is 12,3.