• Degree of precision a value can be stated
    • Precision of a measurement process
  • Numbers with more digits to the right of a decimal indicate more precision
    • --> less uncertainty
  • How finely was a measurement taken?


  • 123 is precise up to the unit place
    • Could be 122.5 rounded up or 123.4 rounded down
  • 120 is precise to the tens place
    • Last digit is zero (not a significant digit)
    • Could be anything from 1225 to 124.9 depending on how the measurement/rounding process is done