Number
Sets
There
are many subsets of numbers that comprise the set of Real Numbers:
Natural
Numbers ...
are a subset of
Whole Numbers ...
which are a subset of
Integers ...
which are a subset
of
Rational Numbers ... {fractions and terminating decimal numbers in
addition to the above numbers}
which are a subset of the Real Numbers.
Irrational numbers are not subsets of all of the above mentioned
sets. Irrational numbers are numbers that are
non-terminating, non-repeating decimal numbers and are very different from Rational
Numbers.
[ ir at the beginning of a word means not”; thus, irrational means not
rational.]
Most often
Irrational numbers can be distinguished from other numbers by the use of the radical sign
. However, if the radicand (the number inside the
radical) is a perfect squared number, you could easily mistake the radical for an
irrational number. For example:
is a Natural number, a Whole number an Integer, a Rational
number, and a Real number.
is a Rational
number and a Real number.
goes on and on forever with the decimals not
repeating nor terminating.
Therefore,
is
an Irrational #.
Irrational numbers are a
subset of the Real Numbers. All numbers that
we will be studying this semester are Real Numbers. That
means that all can be located on the number line.