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Significant Figures. Which is the most precise?. Precision - the number of digits used to express a value. A. 100 B. 100.0 C. 100.00 D. 100.000. What is a Significant Figure?. Significant Figure – a digit that affects a number’s precision, not its value. A. 100 B. 100.0
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Which is the most precise? Precision- the number of digits used to express a value A. 100 B. 100.0 C. 100.00 D. 100.000
What is a Significant Figure? Significant Figure – a digit that affects a number’s precision, not its value A. 100 B. 100.0 C. 100.00 D. 100.000 There are four (and a half) rules for determining which numbers are significant and which aren’t
Rule #1:All nonzero numbers are significant 70 km has one sig fig 550 mi/h has two sig figs 11,257 kg has five sig figs
Rule #2“Middle Zeros” are significant 703 ft has three sig figs 7.03 cm has three sig figs 7003 s has four sig figs
Rule #3“Beginning Zeros” are never significant 0.753 m/s has three sig figs 0.00753 lb has three sig figs
Rule #4“Ending Zeros” are significant if:there is a decimal anywhere in the number 7.000 m has four sig figs 700.0 m has four sig figs
Rule #4.5“Ending Zeros” are not significant if:there is NOT a decimal present in the number 7000 m has one sig. fig. 750 kg has two sig. figs.
Rounding Rules • Often, you will need to round numbers off to the correct order of precision (number of sig figs). • When rounding, • Determine the number of significant digits you need to keep. • Look to the next number • If it is 5 or above, round up. • If it is below 5, round down. • If your number has a decimal, drop all numbers that come after the rounded digit.
