[(1/2+2/3+5/6):7/12 - (2/5)x(5/6)]x(1/4):(5x12/25 - 1si1/3) =
= [(3/6+4/6+5/6)x12/7 - (2/6)] x (1/4) : (12/5-4/3) =
= [(12/6)x12/7 - 1/3] x (1/4) : (36/15-20/15) =
= (2x12/7 - 1/3) x (1/4) : (16/15) =
= (24/7 - 1/3) x 1/4 x 15/16 =
= (72/21 - 7/21) x 1/4 x 15/16 =
= 65/21 x 1/4 x 15/16 =
= 65x5/7x4x16 =
= 325/448