APS Honors



Name Date Period

Mrs. Fran Jiménez - APS Sig Figs!

Rules for determining quantity of significant figures within a measured value:

1 – All non-zero digits are significant.

534.559 = 6 sf

2 – All zeroes sandwiched between other significant digits are significant.

4,005.06 = 6 sf

3 – A zero to the right of a non-zero digit, but to the left of an understood decimal is not significant.

450 = 2 sf

Exceptions: A – If a decimal is actually shown at the end of the number, the zeroes are significant because this indicates that they have indeed been measured as zero.

5300. = 4 sf

B – If a bar is over a zero it is significant as is any zero to its left.

25,000 = 4 sf

4 – A zero to the right of a decimal, but to the left of a nonzero digit is NOT significant unless sandwiched between other nonzero digits.

0.0076 = 2 sf

5 – All zeroes to the right of a decimal and to the right of a nonzero digit are significant because it indicates that they have been measured to be zero.

4.5600 = 5 sf

PRACTICE

How many significant digits are in each of the following measured number expressions? Put your answer neatly on the given line.

a) 23.00 ____ k) 1.0008 ____

b) 4.2508 ____ l) 234.00 ____

c) 232,000 ____ m) 40.0 ____

d) 1,030 ____ n) 12,000 ____

e) 1.00900 ____ o) 103.00687____

f) 0.0045 ____ p) 13 ____

g) 300. ____ q) 10. ____

h) 1200 ____ r) 0.00507 ____

i) 104,240.0058 ____ s) 100,500 ____

j) 4.0 ____ t) 0.4060 ____

Name Date Period

Mrs. Fran Jiménez - APS Sig Figs!

Practice rounding to correct number of significant figures

Round the following values so that they have only 3 significant figures…

5.671 = 34,589 =

56,813 = 0.65075 =

30.37 = 349.7 =

1,249 = 0.000765432 =

100.76 = 239,786.54 =

Practice doing calculations with care for significant figures

Perform the following mathematical expressions using your calculator. Give both the raw mathematical answer and then circle your final answer that has been rounded to have the correct number of sig figs. Assume that all numbers are measured values unless otherwise indicated. For addition and subtraction problems, underline the “last” significant digit in each value as part of your work. For multiplication and division problems, note the number of significant digits in each value in a circle above the value.

A) 3.46 + 0.008 + 10,004.241 + 5.0

B) 23,000 – 12.985

C) 3.24 x 1.608 x 2000

D) 67,000. / 3.75

E) (5.20 x 6.81 ) / 2.0

F) 25.0650 x 4.03

G) 9.000 – 4.2

H) 0.00075 + 0.0532 + 3.72

I) 9.005 / 0.54

J) 440 x 2.4542

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