8*4+(25-17)= 82-21: 7+11= (13-8)*6: 10= 42: (31-8*3)= (90: 10-4)*7= 72: (40-32)*6= 81: 81*9+37= (39-39)*100+36: 6= (6*10-48): 2=

1. 40
2.90
3.3
4.6
5.35
6.46
7.106
8. 6

 8*4+(25-17)= 32+8=40
 (13-8)*6:10=  5*6:10=30:10=3
42:(31-8*3)=42:(31-24)=42:(7)=6
(90:10-4)*7=(9-4)*7=35
72:(40-32)*6=72:(8)*6=54
81:81*9+37=46
(39-39)*100+36:6=6
(6*10-48):2=6