Significant Figure Rules

1. All Nonzeros are significant.523 g =

3 sig figs

4222 cm3=

4 sig figs

2. All numbers between significant figures are significant.4,404 g = 4 sig figs9.005 mm = 4 sig figs5,000,102 mg = 7 sig figs

3. All final zeros past the decimal are significant.9509.90 cm =

6 sig figs

52.000 km =

5 sig figs

4. Zeros used solely as placeholders are NOT significant.42,000 L = 2 sig figs42,000.00 L = 7 sig figs0.000802 g = 3 sig figs

1. Find the part of the problem with the least number of sig figs.142 m x 1552 m x 0.25 m =

Which measurement has the least?

0.25 m only has 2 sig figs.

2. Round your answer so it has that number of sig figs.

142 m x 1552 m x 0.25 m =55,096=

55,000

3. UnitsWhen multiplying, add the exponents.142 m x 1552 m x 0.25 m =55,000 m3

When dividing, subtract the exponents.

12 g3 ÷ 6 g = 2 g2

18 g ÷ 2 cm3 = 9 g/ cm3

1. Find the least accurate measurement in the problem.14.3 g + 99 g + 40 g =

40 g is the least accurate measurement. It is rounded to the nearest 10

2. Make your answer match the least accurate measurement. 14.3 g + 99 g + 40 g =

153.3 g must be rounded to the nearest ten

The answer is 150 g

More Examples300 g - 193 g - 21.2 g =

85.8

Since 300g is the least accurate measurement, your answer must be rounded to the nearest 100.

The answer is 100 g

Examples cont.14.2 m + 12.36 m =

26.56

Since 14.2 is the least accurate measurement, the answer must be rounded to the nearest tenth.

26.6 m