What digits are considered significant in a measurement?

Answer 1

Non-zero digits are always significant. Thus, 569 has three significant digits, and 69.35 has four significant digits. Zeros are sometimes significant and sometimes aren't: # Zeroes placed before other digits are not significant; 0.0968 has three significant digits. # Zeroes placed between other digits are always significant; 70063 kg has five significant digits. # Zeroes placed after other digits but behind a decimal point are significant; 7.90 has three significant digits. # Zeroes at the end of a number are significant only if they are behind a decimal point as in (c). Otherwise, it is impossible to tell if they are significant. For example, in the number 8200, it is not clear if the zeroes are significant or not. The number of significant digits in 8200 is at least two, but could be three or four. To avoid uncertainty, use scientific notation to place significant zeroes behind a decimal point: 8.200 * 103 has four significant digits

8.20 * 103 has three significant digits 8.2 * 103 has two significant digits