12цел 13/48-[9цел17/32- 4цел5/24]; 1цел5/7+3цел11/14-2цел1/4; (18-10цел18/35)-(3цел9/28+2цел3/20)

12 13/48-[ 9 17/32-4 5/24]=6 51/961 5/7+3 11/14-2 1/4= 3 1/4(18-10 18/35)-(3 9/28+2 3/20)= 8 18/35-5 33/70= 3 3/70