Significant Digits Or Significant Figures

Significant Digits or Significant Figures

Rules for counting Sig Figs  Zeros ______a number are always significant  Both 4308 and 40.05 contain ______significant figures  Zeros that ______but set the decimal point (place holders) are ____ significant  470,000 and 0.000047 have ______significant figures  ______zeros that aren't needed to hold the decimal point ______significant  4.00 and 0.00400 have ______significant figures How many significant digits?  12.760  0.00034  9.0034  0.0901  3.8 x 107  1.096 x 10-3  987 600  54 004  -43.803  0.210 Rules for rounding off  Imagine that you want to have 2 significant digits….  If the digit after is smaller than 5 (<5), ______.  Ex: 12. 4 à ____  If the digit after is > 5, ______.  Ex: 12. 6 à ____  If the digit after is 5…  If the digit that you are rounding is ______, ______ Ex: 12,5 à _____  If the digit that you are rounding is ______, ______ Ex: 17.5 à _____ Round off to have 3 significant figures.  1.854  96.019  974 501  273.51  930.8  381.5  0.004 745 Addition and Subtraction with Significant Figures When measurements are added or subtracted, the answer can contain no more ______than the least accurate measurement.  14m/s + 11,8m/s =  0,370m + 0,487 6m =  45,23s – 3,8s =  130,0m – 5,43m =  58,035cm + 4,72cm =

Multiplication and Division with Significant Figures When measurements are multiplied or divided, the answer can contain no more ______than the least accurate measurement.

Exceptions!! “______” numbers are not used to calculate the number of significant digits Example: If 124.79 grams of candy are to be divided among 4 children, how many grams would each child receive? The number “4” is a counting number. The answer would be given with ___ significant digits

“______” are not used to calculate the number of significant digits Example: How many minutes are there in 2.75 hours? The constant value used in this calculation is 60 minutes/hour, but the number of significant digits in “60” is not counted. The answer would be given with ____ significant digits