A **number** is a
quantity associated with a symbol or **numeral** that represents that
quantity. This is constant throughout civilization. Numerals are changeable
because they reflect the written language from different cultures, but they
still represent the same quantity.
The **cardinal numbers**
refer to a collection of items such as the number of animals in a group (i.e.
10 cats). **Ordinal numbers** specify the succession of specific elements
of a group (i.e., the man is first on line). Numbers are grouped into **
irrational** and **rational. **Irrational numbers continue to infinity
and cannot be expressed as a fraction. We will investigate some very famous
irrational numbers in a later chapter. Rational numbers can be expressed as a
fraction or ratio. The **numerator **and **denominator** are **
integers**.
A **ratio **is a
mathematical way of showing a relationship of two numbers, six is to twelve.
We can symbolically use a fraction to make it easier to read 6/12.
Mathematical symbols allows us to compare numbers and find equal proportions,
for example, six is to twelve as three is to six (6/12=3/6). We now are using
numbers to create a **proportion. ** A proportion is an equation with a ratio on each side. It is a statement
that two ratios are equal. |