1. Metric Base Units Meter (m) – length Kilogram (kg) – mass Kelvin (K) – temperature Second (s) – time Mole (mol) – amount of substance

2. Metric Unit Prefixes Kilo- (k) – 1000 10 3 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

3. 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.

4. Significant figures (digits) -- Used to help indicate the accuracy of measurements 142.04 g 5 0.0021 mm 2 1.84 s 3 0.6240 cL 4 87.3010 km 6 0.000302 cm 3 4.02000 cm 3 6 2.908 x 10 8 m/s 4

5. 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

6. 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 km 2  area = 27.0 km 2 mass = 12.04 g volume = 1.8 mL density = 6.688888888 g/ml  density = 6.7 g/ml