43/42+113/56+217/72+361/90
=(1+1/42)+(2+1/56)+(3+1/72)+(4+1/90)
=10+1/42+1/56+1/72+1/90
=10+(1/6-1/7)+(1/7-1/8)+(1/8-1/9)+(1/9-1/10)
=10+1/6-1/10
欢迎提问