Question

1/4X5+1/5X6+1/6X7+1/7X8+1/8X9+1/9X10=多少

1/(4X5)+1/(5X6)+1/(6X7)+1/(7X8)+1/(8X9)+1/(9X10)=多少

Answer 1

1/4X5 + 1/5X6 + 1/6X7 + 1/7X8 + 1/8X9 + 1/9X10
= (1/4 - 1/5) + (1/5 - 1/6) + (1/6 - 1/7) + (1/7 - 1/8) + (1/8 -1/9) + (1/9 - 1/10)
= 1/4 - 1/10
= 3/20

追问

是分母乘

追答

我写的就是分母乘，谢谢

Answer 2

=1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/4-1/10
=3/20

Answer 3

6.995634921

Answer 4

165

追问

过程

Answer 5

3/20