1. Significant Digits Non-zero digits are always significant  291 has three significant digits  29.18 has four significant digits Zeroes placed before other digits are not significant  0.095 has two significant digits Zeroes placed between other digits are always significant  105 volts has three significant digits.

2. Significant Digits … Zeroes placed after other digits but behind a decimal point are significant  2.500 has four significant digits Zeroes at the end of a number are significant only if they are behind a decimal point as in previous case  4900 has two significant digits  4900. has four significant digits

3. Significant Digits … Definitions have infinite significant digits  100 cm in a meter, 60 minutes in an hour, etc. Do not write more digits in an answer (intermediate or final) than the fewest digits in the given data Round-off the answer to appropriate number of digits; however, be careful of the context

4. Significant Digits … Use of scientific notation is less ambiguous  4.900 X 10 3 has four significant digits, 4.90 X 10 3 has three significant digits, 4.9 X 10 3 has two significant digits Click here for a tutorialtutorial