Arithmetic Operations with Numerical Fractions
In technical applications, calculations are usually done with
decimal numbers directly. So, if we need to find a sum such as
we simply use a calculator
(or the equivalent keystrokes on your own calculator), and we
get the answer 0.91666666, which we can then roundoff
appropriately. Obviously, we are getting an approximate answer,
since roundingoff must be done. Often, such a procedure is quite
adequate for the problem being solved.
However, sometimes it is necessary to carry out the arithmetic
with fractions so that the result is an exact answer, often
expressed as a fraction in simplest form. In such instances, you
can use your calculator to check that your answer is not
seriously in error, but you need to do the arithmetic directly
with the fractions.
In the next few notes in this series, we demonstrate how to do
basic arithmetic with numerical fractions as fractions. So, for
example, instead of the decimal answer obtained above, we will be
able to find that
exactly.
The methods described here will also be a useful starting
point later for understanding how to add, subtract, multiply and
divide when algebraic fractions are involved.
