30075: 401 73278: 354 83*502 207*61 180-(90-160: 4)*2 20*6-40+200: 20*3

30075:401= 75

73278:354 = 207

83*502 = 41666

207*61 = 12627

180-(90-160:4)*2 = 180-50*2=180-100=80

20*6-40+200:20*3 = 120-40+30= 110

1) 30075:401=75

2) 73278:354=207

3) 83*502=41,666

4) 207*61=12,627

5) 180-(90-160:4)*2= 180-(90-40)*2= 180-180-80=-80

6) 20*6-40+200:20*3= 120-40+200:60= 80+3,3= 83,3