(2/5+7/12)•30/43-(2: 2целых1/2)•5/32 =

(2/5 + 7/12) * 30/43 - (2 : 2 1/2) * 5/32 = 193/344
1) 2 : 2 1/2 = 2/1 : 5/2 = 2/1 * 2/5 = 4/5
2) 2/5 + 7/12 = (12*2 + 5*7)/60 = 59/60
3) 59/60 * 30/43 = 59/86
4) 4/5 * 5/32 = 1/8
5) 59/86 - 1/8 = (4*59 - 43*1)/344 = 193/344