1.17*(7.5+2.5)+28*7.5=170+7*4*7.5=170+7*30=380
2.412*0.81+(412+125)*0.19+11*9.25
=412*(0.81+0.19)+1.25*(11+8)+11*9.25
=412+ 1.25*8+11*(1.25+9.25)
=412+10+11*11=543
3.(1+0.23+0.34)×(0.23×0.34 )+(1+0.23+0.34)*0.65 -(1+0.23+0.34)*(0.23×0.34 )-0.65×
（0.23+0.34）
=0.65*(1+0.23+0.34-0.23-0.34）=0.65
4.3.57+（7.76-4.33）=3.57+3.43=7
5.6.93-1.83+3.9=5+3.9=8.9
6.121+53-（68+85）=174-153=21
7.31*（4*25）=31*100=3100
8.题目看不懂不知道符号在哪.最好加点括号
9.(1+1/2+1/3+1/4)×（1/2+1/3+1/4）+(1+1/2+1/3+1/4)×1/5-1*(2/1+1/3+4/1)-
(1/2+1/3+1/4+1/5) × (1/2+1/3+1/4)
=1/5*(1+1/2+1/3+1/4-1/2-1/3-1/4)=1/5
10.6/6-1/6+1/42+1/56+1/72+1/90+1/110
=35/42+1/42+1/56+1/72+1/90+1/110
=48/56+1/56+1/72+1/90+1/110
=63/72+1/72+1/90+1/110
=80/90+1/90+1/110=99/110+1/110=10/11
打得很辛苦.给分吧