proper fraction
noun [ C ] mathematics specialized uk/ˌprɒp.ə ˈfræk.ʃən/ us/ˌprɑː.pɚ ˈfræk.ʃən/
（数学中的）真分数
a fraction in which the number below the line is larger than the number above it
3/4 and 5/8 are proper fractions. 3／4和5／8都是真分数。