1.
(-30 3/4)÷(-15)
2.(-0.3)÷(+1/3)÷(-9)
3.
(-2 1/2)÷(-3)×(-3 1/3)
4.(-49)÷2 1/3× 3/7÷(-16)
步骤要详细 其中有些分数是几又几分之几
有理数的除法是:
1、两个有理数相除,同号得正,异号得负,并把绝对值相除。0除以任何非0的数都得0,且0不能做除数。
2、除以任何一个不为0的数,等于乘这个数的倒数。
3、有理数混合运算时,加减、乘除都是同级运算,同级运算是依照从左至右的运算顺序,即先算乘除,再算加减。有理数的除法可以化为乘法,步骤为:将所有除数转化为其倒数,所有除法转化为乘法,运用乘法运算律求出结果。
1、两个有理数相除,同号得正,异号得负,并把绝对值相除。0除以任何非0的数都得0,且0不能做除数。
2、除以任何一个不为0的数,等于乘这个数的倒数。
3、有理数混合运算时,加减、乘除都是同级运算,同级运算是依照从左至右的运算顺序,即先算乘除,再算加减。有理数的除法可以化为乘法,步骤为:将所有除数转化为其倒数,所有除法转化为乘法,运用乘法运算律求出结果。
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第1个回答 2009-10-31
(-30- 3/4)÷(-15)
=(-30)÷(-15)-(3/4)÷(-15)
=2+3/4*1/15
=2+1/20
=2又1/20
(-0.3)÷(+1/3)÷(-9)
=(-3/10)÷(1/3)÷(-9)
=3/10÷(1/3*9)
=3/10÷3
=3/10*1/3
=1/10
(-2 1/2)÷(-3)×(-3 1/3)
=-5/2*1/3*10/3
=-25/9
=-2-7/9
=-2又7/9
(-49)÷2 1/3× 3/7÷(-16)
=49*3/7*3/7*1/16
=49*9/49*1/16
=9/16本回答被网友采纳
=(-30)÷(-15)-(3/4)÷(-15)
=2+3/4*1/15
=2+1/20
=2又1/20
(-0.3)÷(+1/3)÷(-9)
=(-3/10)÷(1/3)÷(-9)
=3/10÷(1/3*9)
=3/10÷3
=3/10*1/3
=1/10
(-2 1/2)÷(-3)×(-3 1/3)
=-5/2*1/3*10/3
=-25/9
=-2-7/9
=-2又7/9
(-49)÷2 1/3× 3/7÷(-16)
=49*3/7*3/7*1/16
=49*9/49*1/16
=9/16本回答被网友采纳
第2个回答 2009-10-31
1.
(-30 3/4)÷(-15)
=123/4*1/15
=123/60
2.(-0.3)÷(+1/3)÷(-9)
=-3/10*3÷(-9)
=9/10*1/9
=1/10
3.
(-2 1/2)÷(-3)×(-3 1/3)
=5/2*1/3×(-3 1/3)
=-5/6*3/10
=-1/4
4.(-49)÷2 1/3× 3/7÷(-16)
=(-49)*7/3*3/7÷(-16)
=-9÷(-16)
=9/16
(-30 3/4)÷(-15)
=123/4*1/15
=123/60
2.(-0.3)÷(+1/3)÷(-9)
=-3/10*3÷(-9)
=9/10*1/9
=1/10
3.
(-2 1/2)÷(-3)×(-3 1/3)
=5/2*1/3×(-3 1/3)
=-5/6*3/10
=-1/4
4.(-49)÷2 1/3× 3/7÷(-16)
=(-49)*7/3*3/7÷(-16)
=-9÷(-16)
=9/16
第3个回答 2009-10-31
(-30 3/4)÷(-15)
=-(30*4+3)/4/(-15)
=-(40*3+3)/(-15)/4
=-(401*3)/((-5)*3)/4
=-401/(-5)/4
=401/20
(-0.3)÷(+1/3)÷(-9)
=(0.1*3)/(1/3)/((-1)*3*3)
=0.1/(-1)
=-0.1
(-2 1/2)÷(-3)×(-3 1/3)
=(-(2*2+1)/2)/(-3)*(-(3*3+1)/3)
=(5/2)/3*(-10/3)
=(5/2)/3*(((-5)*2)/3)
=5/3*(-5)/3
=-25/3
(-49)÷2 1/3× 3/7÷(-16)
=(-7)*7/((2*3+1)/3)*3/7/(-16)
=(-7)*7/(7/3)*3/7/(-16)
=(-7)*7/((7/3)*3/7)/(-16)
=(-7)*7/(-16)
=49/16
=-(30*4+3)/4/(-15)
=-(40*3+3)/(-15)/4
=-(401*3)/((-5)*3)/4
=-401/(-5)/4
=401/20
(-0.3)÷(+1/3)÷(-9)
=(0.1*3)/(1/3)/((-1)*3*3)
=0.1/(-1)
=-0.1
(-2 1/2)÷(-3)×(-3 1/3)
=(-(2*2+1)/2)/(-3)*(-(3*3+1)/3)
=(5/2)/3*(-10/3)
=(5/2)/3*(((-5)*2)/3)
=5/3*(-5)/3
=-25/3
(-49)÷2 1/3× 3/7÷(-16)
=(-7)*7/((2*3+1)/3)*3/7/(-16)
=(-7)*7/(7/3)*3/7/(-16)
=(-7)*7/((7/3)*3/7)/(-16)
=(-7)*7/(-16)
=49/16
第4个回答 2009-10-31
1=(30*4+3)/(4*15)=41/20
2=(3/10)*(3)*(1/9)=1/10
3=-[(5/2)*(1/3)*(10/3)]=25/9
4=49*(3/7)*(3/7)*(1/16)=9/16
这些中学口算题我只能这么详细了
2=(3/10)*(3)*(1/9)=1/10
3=-[(5/2)*(1/3)*(10/3)]=25/9
4=49*(3/7)*(3/7)*(1/16)=9/16
这些中学口算题我只能这么详细了