Chemistry
EXTRA Sig Figs and Rounding 2
Minniear
Round to 1 sig fig
1) 23.90
2) 57.40
3) 91.5
4) 44.50
6) 57.40
7) 91.5
8) 44.50
9) 8.68501
10) 2.874 X 10-3
11) 78,299
12) 0.09350
13) 6.62505 X 104
14) 7, 421
15) 585.500
16) 299.978
Round to 2 sig figs
5) 23.90
Round to 3 sig figs
Operate, round as necessary to report the answer with the proper number of sig figs
17) (2 mm)(1.3 mm)(0.87 mm)
18) (2.0 mm)(1.3 mm)(0.87 mm)
19)874.250 m ÷ 20.0
20)874.250 m ÷ 20
21) 125.575 – 15.00
22) 125.575 - 15
23) Calculate the average of 12.73, 15.5, and 14.24
Chemistry
EXTRA Sig Figs and Rounding 2
Minniear
Round to 1 sig fig
1) 20
2) 60
3) 90
4) 40
6) 57
7) 92 odd, so round up 8) 44 even, so leave it
10) 2.87 X 10-3
11) 78,300
Round to 2 sig figs
5) 24
Round to 3 sig figs
9) 8.69
501 is over half
way, so round up
13) 6.63 X 104
Only the base has sig figs
and dropping the last
digit without replacing it
with a zero does not
affect the magnitude of
the number. Replacing
the 4 with a zero would
not reduce the sig figs
anyway; it is after the
decimal point.
14) 7, 420
12) 0.0935
Here we must
replace the
numbers with zeros
or change the
magnitude of the
number. Trailing
zeros with no
decimal point do
not count anyway.
15) 585
505 is over
halfway, so
round up
16) 3.00 x 102
This is one of those times when it
must be reported in scientific notation
in order to show proper sig figs
Operate, round as necessary to report the answer with the proper number of sig figs
17) 2.262 mm3
2 mm3
18) 2.262 mm3
2.3 mm3
19) 43.7125 m
43.7 m
20) 43.7125 m
40 m
Chemistry
EXTRA Sig Figs and Rounding 2
21) 110.58
22) 111
When adding and
subtracting, the answer is
limited by the number of
decimal places in the
input rather than the
total number of sig figs in
the input. Also, .575
rounds to .58 because the
7 is odd.
23) 14.15666667
Since there are no decimals in part of
the input, we get no decimals in the
answer. It must be rounded up.
14.2
Complete the calculation before doing
any rounding; round at the end and
not as you go. Remember that the 3
you divide by for the average is a
counting number, not a
measurement. It has no effect on the
sig figs. You are allowed 1 decimal in
your answer.
Minniear