# Metric SI Prefixes and Abbreviations You should know

Metric (SI) Prefixes and Abbreviations You should know the ones with the red arrow. → → → → →

Determining Whether Zeros Are Significant Figures (All nonzero digits are significant. ) 5700. 0 has five significant figures 5700. has four 5700 is ambiguous. It may be 2, 3 or 4. Assume TWO. You can specify with sci. notation: 5. 7 x 103 5. 700 x 103

Significant Figures – Additional Rules 1. Zeros between other significant digits are always significant. Examples: 100. 1 m and 100. 0 m have 4 significant figures 100. 05 m and 1000. 0 m have 5 significant figures 2. Zeros at the end of a number but to the left of the decimal point are significant if and only if the decimal point is explicitly stated. Examples: 100. m has 3 significant figures 100 m has 1 significant figure unless otherwise clarified

Rules for Calculating with Significant Figures Sig figs matter! Measurements have limited precision – therefore calculated values based on those measurements also have limited precision! When adding or subtracting, the answer should have the smallest number of decimal places of any of the terms. (All places are decimal places, whether they are to the left or right of the decimal point: 110 + 52. 3 = 162. 3 Round to 160) When multiplying or dividing, the answer should have the smallest number of significant figures of any of the terms.

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