(6*9-3*4)/6+(7*4+21/3)/5*7-18/9
(54-12):6+(28+7):35-2= 42:6+35:35-2= 7+1-2=
8-2= 6
(6*9-3*4)/6+(7*4+21/3)/5*7-18/9=7+35/5*7=56