Also what is the definition of a

- The
**Numerator**of a fraction is the number above the slash:^{1}/_{2}.

- The
**Denominator**of a fraction is the number below the slash:^{1}/_{2}.

The numerator represents a number of equal parts, and the denominator, which cannot be zero, indicates how many of those parts make up the whole. Example, think of a pizza cut into eight slices (8 is the denominator) and five slices (5 is the numerator) have been eaten. So let's show these facts as fractions:

- One whole pizza is represented as one or as the fraction
^{8}/_{8}. This means the pizza is cut into eight slices but none of the slices have been eaten so far.

- Now five slices of the pizza with eight slices have been
eaten. Shown as a fraction
^{5}/_{8}or 5 of 8 slices have been eaten.

- So how much of the pizza remains? Well, we started with eight
slices and five have been eaten:
^{8}/_{8}-^{5}/_{8}=^{3}/_{8}. So 3 of 8 slices of pizza are left.

One very important fact about fractions: the denominator can
never be zero! For example the fractions ^{1}/_{0}, ^{-4}/_{0},
and ^{0}/_{0} are all considered undefined i.e. they make no sense
in mathematics.

Recommended reading: Proper Fractions and Improper Fractions.

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