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Significant Figures. Rules. All nonzeroes are significant Zeroes in-between are significant Zeroes to the left are not significant Zeroes to the right are not significant unless they follow a decimal. All numbers in scientific notation are significant
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Rules • All nonzeroes are significant • Zeroes in-between are significant • Zeroes to the left are not significant • Zeroes to the right are not significant unless they follow a decimal. • All numbers in scientific notation are significant • Exact numbers are obtained by counting or by using definitions such as 1 in = 2.54 cm, and are considered infinite in significance
Adding and Subtracting • Always use the least significant decimal place. • example: • 1253.747 + 1.1 = 1254.8 = 1254.9 round up 1253.757 + 1.1 .0365578 - .00223 = .03433 or 3.433 X 10-2
Multiplying and Dividing • All ways go by the least number of significant figures. examples: 1253.747 X 1.1 = 1379.1217 No =1400 or 1.4 x 103
Combining the math • 55.657 -55.654 X .033 = 4.54 • 2 x 10-5 • Note the level of significance produced by the subtraction operation in the numerator.
Exact Numbers • 1 dozen eggs • 25 students • 2.54 cm = 1 in • 6.02213 x 1023 NOT