初中数学题(初一的简便方法)8道数学题……急!要正确(1)(-10)*(-8.24

1个回答

  • (1)(-10)*(-8.24)*(-0.1)=-(10*0.1*8.24)=-(1*8.24)=-8.24;

    (2)(-4又1/20)*1.25*(-8)=(81/20)*(1.25*8)=(81/20)*10=81/2为四十又二分之一 ;

    (3)(-7/9+5/6+3/4-7/18)*36=(-14/18-7/18)*36+(5/6)*36+(3/4)*36

    =(-21)*2+30+27=-42+57=15;

    (4)31又15/16*(-8)=(31+15/16)*(-8)=31*(-8)+15/16*(-8)=-248-15/2=-248-7-1/2=-255-1/2

    =-(255+1/2)

    为-二百五十五又二分之一.

    (5)2/3*(-1/2)*(-3又1/3)*(-3/5)=-(2/3)*(3+1/3)*(1/2)*(3/5)=-(2+2/9)*(3/10)

    =-(20/9)*(3/10)=-2/3;

    (6)【-7/12+3/4-5/6-(-5/18)】*(-36)=-[(-7/12)*36+(3/4)*36+(5/18)*36]

    =-[-7*3+3*9+5*2]=-[-21+27+10]=-16;

    (7)(-3/5)*(10-1又2/3-4又1/6)=(-3/5)*(10-5/3-25/6)

    =(-3/5)*10-(-3/5)*(5/3)-(-3/5)*(25/6)=-6+1+5/2=-5+(5+1/2)-5+5+1/2=1/2;

    (8)(-35又6/7)*4=-(35+6/7)*4=-[35*4+(6/7)*4]=-(140+24/7)=负一百四十三又七分之三.