CHAPTER6 Decimals
In This Chapter
- The system of decimal
fractions - Writing very small num-
bers in scientific notation - Adding and subtracting
decimals - Multiplying and dividing
decimals - Converting between frac-
tions and decimals
Not every number system in history had a way to represent
parts of a whole but our system does. In fact, it has two.
You’ve already met common fractions, the ones that are
written as a quotient of two integers. In this chapter, you’ll get
to know decimal fractions.
A decimal fraction, or as most people call it, a decimal, is a
representation of part of a whole written in a way that fits
into our decimal place value system. In this chapter, you’ll
see how to extend the place value system to include parts of
a whole, and how to write very small numbers in scientific
notation. You’ll look at each of the operations of arithmetic
when decimals are involved, and you’ll see that one of the
advantages of decimals is that they fit nicely into the methods
you already know. Just in case you need to switch between
the two ways of writing fractions, you’ll learn to convert from
common fractions to decimal fractions and back.