分数
分子または分母が分数で表される分数を繁分数(はんぶんすう、英: compound fraction, complex fraction)という。例えば、
a b c , b c a , a b c d {\displaystyle {\frac {\;a\;}{\;{\tfrac {b}{c}}\;}},\quad {\frac {\;{\tfrac {b}{c}}\;}{\;a\;}},\quad {\frac {\;{\tfrac {a}{b}}\;}{\;{\tfrac {c}{d}}\;}}}
や
a b + c d , b + c d a , a + b c d + e f {\displaystyle {\frac {\;a\;}{b+\;{\tfrac {c}{d}}\;}},\quad {\frac {\;b+{\tfrac {c}{d}}\;}{\;a\;}},\quad {\frac {\;a+{\tfrac {b}{c}}\;}{\;d+{\tfrac {e}{f}}\;}}}