18×19+19×20+20×21+21×22/36×38+38×40+40×42+42×44
问题描述：
18×19+19×20+20×21+21×22/36×38+38×40+40×42+42×44
答
(18×19+19×20+20×21+21×22)/(36×38+38×40+40×42+42×44)=(18×19+19×20+20×21+21×22)/(2×18×2×19+2×19×2×20+2×20×2×21+2×21×2×22)=(18×19+19×20+20×21+21×22)/(4×18×19+4×19×20+4×20...