Now that you've learned the importance of recording measurements
to the proper number of significant figures, it is very likely that you will
be doing calculations with these measurements. The type of calculations that
you will most likely carry out are the following types of mathematical operations:

addition

subtraction

multiplication

division

It is important to know how to determine the proper number
of significant figures in your answer AFTER you
have completed mathematical manipulations of the measurements.

For example,

let's say you have taken the following measurements for
calculating the area of a table-top.

width = 50.996 cm
length = 75.4 cm

To calculate the area of the table-top, the area would equal
50.996 cm x 75.4 cm. The calculator answer is

When you record the area of the table-top, should you record

area = 3845.0984 cm^{2}
(No!)

The calculator displays too many figures. You need to know some rules
in determining the proper number of significant figures of an answer which resulted
from a mathematical operation. Read on ... (the answer to this example is in
section 1.7.3).