作业帮1又1/3-7/12+9/20-11/30+13/42-15/56+17/72
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/09 11:31:39
1又1/3-7/12+9/20-11/30+13/42-15/56+17/72
1又1/3-7/12+9/20-11/30+13/42-15/56+17/72
1又1/3-7/12+9/20-11/30+13/42-15/56+17/72
=1/3-(3+4)/(3*4)+(4+5)/(4*5)-(5+6)/(5*6)+(6+7)/42-(7+8)/(7*8)+(8+9)/(8*9)
=1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8+1/8+1/9
=10/9