(1/14-1/15):(1/15-1/16)×(1/16-1/17):(1/17:1/18)

Question

(1/14-1/15):(1/15-1/16)×(1/16-1/17):(1/17:1/18)

Answer 1

1/210: 1/240*1/272:1/306= 240/210*306/272= 8/7*9/8=7/9