Significant Digits and Scientific Notation Handout
1. How many significant digits are there in each of the following?
a) 146.32 cm
b) 700 m
c) 700. m
d) 700.5 m
e) 0.00346 kg
f) 1.00346 kg
g) 3.46 x 10-3 kg
h) 1.38 cm
i) 3.0 x 108 m/s
j) 2640 m/s
k) 2.640 m/s
l) 28.0 cm
2. Round off each of the following to two significant digits:
a) 5.934
b) 4.683
c) 76.9
e) 0.0181
f) 34611
3. Express the following in scientific notation:
a) 954
b) 321.0
c) 6784
e) 6400.
d) 0.34499
f) 0.0064
g) 0.800
d) 6400
h) 0.00015
i) 300 000 000
4. Express the following numbers in decimal notation:
a) 3.2 x 105
b) 3.2 x 10-5
c) 3.2 x 100
e) 4.96 x 10-4
d) 8.7912 x 102
f) 3 x 108
5. Calculate each of the following. Express each of your answers in the correct number of
significant digits:
a) 21.36 + 2.8 + 35.348 + 2.9164
b) 147.845 – 121.1
c) 54.612  3.0
d) The area of a rectangle 35.66 cm long
and 9.1 cm wide.
6. Calculate the value of each of the following, expressing your answers in scientific
notation to the correct number of significant digits.
a) (4.0 x 105)(2.0 x 103)
4.0 105
b)
2.0 103
c) (2.03)2 x 102
d) (5.0 x 4.0)2 x 104
27  103
e)
3.0  10 4
7. Three steel spheres have masses of 12.62 g, 13.0 g and 12.882 g. Find the average
mass of the steel spheres.
8. A car travels 250.0 m in 1.00 minute. Calculate its average speed in m/s and km/h.
Answers
1. How many significant digits are there in each of the following?
a) 5
b) 1
c) 3
d) 4
e) 3
f) 6
g) 3
h) 3
i) 2
j) 3
k) 4
l) 3
2. Round off each of the following to two significant digits:
a) 5.9
b) 4.7
c) 77
e) 0.018
d) 0.34
f) 35 000
3. Express the following in scientific notation:
a) 9.54 x 102
b) 3.210 x 102
c) 6.784 x 103
d) 6.4 x 103
e) 6.400 x 103
h) 1.5 x 10-4
f) 6.4 x 10-4
g) 8.00 x 10-1
i) 3 x 108
4. Express the following numbers in decimal notation:
a) 320 000
b) 0.000 032
c) 3.2
e) 0.000 496
d) 879.12
f) 300 000 000
5. Calculate each of the following. Express each of your answers in the correct number of
significant digits:
a) 62.4
b) 26.7
c) 18
d) 320 cm2
6. Calculate the value of each of the following, expressing your answers in scientific
notation to the correct number of significant digits.
a) 8.0 x 108
b) 2.0 x 102
c) 6.4 x 103
d) 4.0 x 106
e) 9.0 x 107
7. 12.8 g
8. 4.17 m/s and 15.0 km/h
Remember that the number 60 used in 60 s/min and in 60 min/h is NOT a measured
quantity. Thus the answers have three significant digits, the same number as in 1.00 min.