Rule #1: All non-zero digits are significant.
Rule #2: Zeros in front of a number are not significant.
Rule #3: Zeros between non-zero digits are significant.
Rule #4: Zeros at the end of a number are significant if there is a decimal point in the number.
Version Number 2
Use this diagram to help determine the number of significant figures in a measured value…
PacificAtlantic
If the decimal point is present, start counting digits from the Pacific (left) side,
starting with the first non-zero digit.
0.003100
(4 sig. figs.)
If the decimal point is absent, start counting digits from the Atlantic (right) side,
starting with the first non-zero digit.
31,400
( 3 sig. figs.)
Examples
HIGHLIGHT TO REVEAL ANSWER
0.0203
3 significant figures
2.50
3 significant figures
2500
2 significant figures
3.7 x 109
2 significant figures
45009
5 significant figures
100.
3 significant figures
10200
3 – the zeros 10200 are ambiguous and 10200 is trapped
34000.00
7 – the zeros 34000.00 indicate precision and 34000.00 are trapped
0.0600
3 – the zeros 0.0600 are place holding and 0.0600 indicate precision
0.0058363
5 – the zeros 0.0058363 are place holding
0.508
3 – the zero 0.508 is place holding and 0.508 is trapped
5007.00
6 – the zeros 5007.00 are trapped and 5007.00 indicate precision
2.40 x 104
3 – the zero indicates precision
0.005670
4 – the 0.00 part is for place holder and the trailing zero is significant
54000
2 – the zeros in 54000 are ambiguous since the decimal is not shown
