Significant Digits
Rules for determining how many SD’s are in a number If it is not zero, it IS significant! Ex: all digits are significant in 45.2 cm 91,722 mL 1.2 kg Zeros in a “zero sandwich ARE significant! Ex: all significant in 405 Mm 23,009 L 100,003 ng
Rules for determining how many SD’s are in a number If no decimal is showing, zeros to the right ARE NOT significant! Zeros are not significant in: 3400 dg 300 L 12,450 pm In small decimal numbers, zeros to the left ARE NOT significant! 0.0023 ng 0.231 m 0.000056 kL
How many SD’s in: 506 L 11.09 mg 5600 km 0.0026 dL 45.00 s 0.000650 mm
Multiplication/Division using SD’s Least total SD’s! The number with the smallest amount of significant digits determines how many SD’s are in your answer Examples: 5.670 m X 3.4 m = 19 m2 45.60 m / 3.70 s = 12.3 m/s
Addition and Subtraction Using SD’s Least significant placeholder The number with the least significant placeholder determines the least significant placeholder in your answer. Ex. 409.34 cm – 23.7 cm = 385.6 cm 3.85 g + 24.901 g + 200.7 g = 229.5 g