28/67×(10 11/13-2 11/13÷ 1/2)÷3 1/2=
3 2 1. 4 28/67×(10 11/13-2 11/13:1/2):3 1/2 = 8/13 1)2 11/13:1/2=74/13 2)141/13-74/13=67/13 3)28/67×67/13=28/13 4)28/13:7/2=8/13