12/1+23/1+34/1+...+89/1+9*10/1简算

来源：学生作业帮助网编辑：作业帮时间：2024/05/03 19:05:37

1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1简算
1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1简算

1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1简算
二分之一写作1/2
1/1x2+1/2x3+1/3x4+...+1/9x10
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)
=1-1/10
=9/10

1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1
=1-2/1+2/1-3/1+3/1-4/1+……+8/1-9/1+9/1-10/1
=1-10/1
=10/9
=0.9

1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1
=1-2/1+2/1-3/1+3/1-4/1+....+8/1-9/1+9/1-10/1
=1-10/1
=10/9