Name ____________________Period _____

Significant Figures Practice

As you saw in the previous assignment, not all digits or figures in a measurement are “significant”. The only significant digits are the digits one is certain of plus the one estimated digit. Many times zeroes are just placeholders and are not “significant.”

Rules for Significant Figures:1. Leading zeroes are never significant.

Example: 0.00682 has 3 significant figures (6.82 x 10-3)2. Zeroes in the middle of a measurement are always significant.

Example: 10.72 has 4 significant figures (1.072 x 101)3. Trailing zeroes are only significant if after a decimal point.

Example: 300 has 1 significant figure (3 x 102)Example: 0.300 has 3 significant figures (3.00 x 10-1)

HINT: If you change to scientific notation you will always know the number of significant figures.

4. Addition or Subtraction: The answer only has as many places as the measurement with least places.

Example: 5. Multiplication or Division: The answer contains the same

number of significant figures as the measurement with the least number of significant digits.

Example:

Practice: Tell how many significant figures are in each number:1. 0.542. 106

3. 54.204. 0.003425. 10006. 100787. 90658. 0.7209. 100.050010. 6080

Perform the following math problems and record your calculated answer and then the answer with the correct number of significant figures. Also, remember to put correct units.Problem Calculated

AnswerAnswer with correct number of significant figures

6.034 cm + 12.89 cm

5.8 mL – 2.893 mL

12.543 m – 3.56 m

16 g + 13.45 g

22.4 L + 16.76 L

23.6 m x 13.278 m

17 cm x 10 cm

32.793 mL/13.2 mL

78.4 km/ 126 km

13.458 mm x 6703 mm