計算:一又四分之一-9/20+11/30-13/42+15/56-17/72+19/90

計算:一又四分之一-9/20+11/30-13/42+15/56-17/72+19/90


一又四分之一-9/20+11/30-13/42+15/56-17/72+19/90 =(1+1/4)-(1/4+1//5)+(1/5+1/6)-(1/6+1/7)+(1/7+1/8)-(1/8+1/9)+(1/9+1/10)=1+1/4-1/4-1//5+1/5+1/6-1/6-1/7+1/7+1/8-1/8-1/9+1/9+1/10=1+1/10=11/1…