(1/2*3/4)*(2/3*4/5)*(5/6*7/8)*(6/7*8/9) помогите плжалуйста

(1/2*3/4)*(2/3*4/5)*(5/6*7/8)*(6/7*8/9) = 3/8*8/15*35/48*48/63= 1/5*35/48*48/63=7/48*48/63=1/9