求初一(上)数学运算题20道有理数的 我说....

2个回答

  • -13×三分之二-0.34×七分之二+三分之一×(-13)-七分之五*0.34

    =-13×2/3 -0.34×2/7 -13×1/3 -5/7 ×0.34

    =-13×(2/3+1/3) -0.34×(2/7+5/7)

    =-13×1 -0.34×1

    =-13.34

    (2×3×4×5)×(二分之一-三分之一-四分之一+五分之一)

    =(2×3×4×5)×(1/2-1/3 -1/4 +1/5)

    =(2×3×4×5)×(1/2)-(2×3×4×5)×(1/3)-(2×3×4×5)×(1/4)+(2×3×4×5)×(1/5)

    =3×4×5-2×4×5-2×3×5+2×3×4

    =60-40-30+24

    =14

    -1.57×(+21.8)+6.28×(-24.7)-3.14×39.7

    =-1.57×21.8 +1.57×4×(-24.7) -1.57×2×39.7=-1.57(21.8+4×24.7+2×39.7)

    =-1.57×200

    =-314

    -38)+52+118+(-62)= -100+170=70

    抱歉,题有点少,但答案都是一步步算出来的

    12+35+(-23)+0= 47-23=24

    (-6)+8+(-4)+12 = 10

    27+(-26)+33+(-27)=33-26=7

    39+[-23]+0+[-16]= 39-39=0

    [-18]+29+[-52]+60= 19

    [-3]+[-2]+[-1]+0+1+2= -3

    [-301]+125+301+[-75]= 125-75=40

    (-7分之1)+(-7分之2)+1又7分之3 =1

    -0.5-(-3 )+2.75-(+7 )2.75-10.5=-7.75

    39+[-23]+0+[-16]= 0

    [-18]+[-52]+60= -10

    [-3]+[-2]+[-1]+0+1+2= -3