6 3/4:9+24:6/7-1/9:4/21

Question

6 3/4:9+24:6/7-1/9:4/21

Answer 1

27/4:9+24:6/7-1/9:4/21= 27/4*1/9+24*7/6-1/9*21/4= 3/4+4*7-7/12= 9/12+336/12-7/12= 338/12= 169/6= 28 1/6