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) – Base unit deci- (d) – 0.1 1/10 centi- (c) /100 milli- (m) /1000 micro- (µ) –

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 g mm s cL km cm cm x 10 8 m/s 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 cm cm cm = 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 = km area = km 2  area = 27.0 km 2 mass = g volume = 1.8 mL density = g/ml  density = 6.7 g/ml