A fraction where both top and bottom numbers are integers.
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.)
../numbers/images/ani-frac-pick.js
See: Integer