用简便方法算:1⼀2*3+1⼀3*4+1⼀4*5+1⼀5*6+1⼀6*7+1⼀7*8+1⼀8*9+1⼀9*10

2024-11-15 08:13:16
推荐回答(1个)
回答1:

=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/7-1/8+1/8-1/9+1/9-1/10
=1/2-1/10
=2/5