How many significant digits?
4 All significant figures count from the first non zero number regardless of any other rules. If there is no decimal point then all the zeros after the last non-zero number are NOT significant. If there is a decimal point then all the zeros after the first non-zero number ARE significant. 5.000 = 4 sig figures. (all zeros after first non-zero count because of decimal point) 5000 = 1 sig fig, no decimal point 0.0005 = 1 sig figure, only number after first non-zero count 0.00050 = 2 sig figures 5.0005 = 5 sig figures If there is no decimal point then a zero after the last non-zero number is not counted as significant 500 = 1 sig figure 500.
