分母分别是27,60,72的最简分数,他们的最小公分母是答:解: 最简真分数 :1/27, 2/27, 4/27, 5/27,7/27, 8/27, 10/27, 11/27, 13/27, 14/27,16/27,17/27, 19/27, 20/27, 22/27, 25/27, 26/27;1/60, 7/60, 11/60, 13/60, 17/60, 19/60, 23/60, 29/60, 31/60, 37/60, 41/60,43/60, 47/60, 49/60, ...
以77为分母的最简真分数一共有()个,它们的和是()答:77=7*11,所以分母为77的分数1/77,2/77,3/77,...76/77,77/77中除了7/77,11/77,77/77外都是真分数,总共有77--=74个,他们的和为(1/77+2/77+3/77+...+76/77)-7/77-11/77 =(1/77+76/77)*76/2-(18/77)=38-18/77 =37又59/77....