1.（1+2.3+3.4）*（2.3+3.4+6.5）-（1+2.3+3.4+6.5）*（2.3+3.4）

　　=(1.2+2.3+3.4)x(2.3+3.4)+(1+2.3+3.4)x6.5-(1+2.3+3.4)x(2.3+3.4)-6.5x(2.3+3.4)=6.5x(1+2.3+3.4-2.3-3.4)=6.5

　　2.8.8-0.8*8.8-0.8=8.8x0.2-0.8=0.8x(2.2-1)=(1-0.2)(1+0.2)=1-0.04=0.96

　　3.（2.8-2.8*0.6）/（0.6+0.52）=(2.8x0.4)/1.12=2.8/2.8=1

　　4.（6.2*1.25+1.25*2.6）/2.2=1.25x8.8/2.2=1.25x4=5

　　5.（1.25*2.7*5.1）/（8.1*0.25*1.7）=(0.25x5x3x0.9x1.7x3)/(9x0.9x0.25x1.7)=5

　　6.（0.8*0.6/1.2）/0.25=4x0.8x0.6/(2x0.6)=1.6

　　7[0.35/(3.74-3.24)/0.4]*0.28=（0.35/0.5）/0.4x0.28=7/4x0.28=7x0.07=0.49

　　83.7-3*0.7-3.7*0.6=3.7x0.4-3x0.7=1.48-2.1=-0.62