Transcript Significant figures (digits)

Metric Base Units
Meter (m) – length
Kilogram (kg) – mass
Kelvin (K) – temperature
Second (s) – time
Mole (mol) – amount of
substance
Metric Unit Prefixes
Kilo- (k) – 1000 103
Base unit
deci- (d) – 0.1 1/10
centi- (c) - 0.01 1/100
milli- (m) - 0.001 1/1000
micro- (µ) – 0.000001 10-6
Measurements and Significant
Digits
When taking measurements, include all
the numbers you know for sure and
one uncertain, guessed at, number.
The guessed at number indicates
where between the smallest marking
you are.
Significant figures (digits)
-- Used to help indicate the accuracy of
measurements
142.04 g
0.0021 mm
1.84 s
0.6240 cL
87.3010 km
0.000302 cm
4.02000 cm3
2.908 x 108 m/s
5
2
3
4
6
3
6
4
Calculations with significant figures
Addition and subtraction
Answer should have as few digits to the
right of the decimal as the least of
what you add or subtract.
Example:
4.13 cm + 2.1435 cm + 1.1 cm + 3.901 cm
= 11.2745 cm 
= 11.3 cm
Multiplication and division
The answer should only have as many
significant digits as the least in what is
being multiplied or divided.
Examples:
length = 6.43 km width = 4.2040 km
area = 27.03172 km2
 area = 27.0 km2
mass = 12.04 g volume = 1.8 mL
density = 6.688888888 g/ml
 density = 6.7 g/ml