1).328 ×12-435:15=3907
1. 435:15 = 29
2. 328 х 12 = 3936
3. 3936 - 29 = 3907
2).(256:16-3)×25=300
1. 256:16 = 16
2. 15 -3 = 12
3.12 х 25 = 300
3).(178:2+15)×11= 1144
1. 178:2 = 89
2. 89+15 = 104
3.104 х 11 = 1144
4).(165:11+78):31 = 3
1. 165:11 = 15
2.15+78 = 93
3. 93:31 = 3