A fraction where both top and bottom are integers.

Example:

But

Example:

^{1}/_{2}and^{3}/_{4}are both Common Fractions.But

^{1.2}/_{4}is NOT a Common Fraction.*(Note: sometimes "Common Fraction" is used to mean "not a Decimal Fraction", but Decimal Fractions also have integers at top and bottom, so are really also Common Fractions.)*See: Integer