По быстрее а)3: 1 1/2 + 5: 1 1/4 = б) 0.7 * 1.3+5.1 : 0.17 = в) ( 10 2/3 - 5 1/3) : 3 1/3 = г) 31.7 : 63.4 - 23.4 : 11.7 =

А) 3:1(1/2)+5:1(1/4)=3:(3/2)+5:(5/4)=3×2/3+5×4/5=2+4=6;

б) 0,7×1,3+5,1:0,17=(7/10)×(13/10)+(51/10):(17/100)=91/100+(51×100/10×17)=(91/100)+30=0,91+30=30,91;

в) (10(2/3)-5(1/3)):3(1/3)=((32-16)/3):(10/3)=(16×3)/(3×10)=16/10=1,6;

г) 31,7:63,4-23,4:11,7=(317/10):(634/10)-(234/10):(117/10)=(317×10/634×10)-(234×10/117×10)=(1/2)-2=0,5-2=-1,5