Let, x=0.125125125… …(i)

Multiplying this equation by 1000 on both the sides so that repetitive terms cancel out and we get:

1000x=125.125125125… …(ii)

Equation (ii)-(i),

⇒ 1000x-x=125.125125125-0.125125125=125

⇒ 999x=125

⇒