数学乘法分配律(-1/30)÷(2/3-1/10+1/6-2/5)计算怎样巧算?再计算:(-1÷42)÷(1÷6-3÷14+2÷3-2÷7),这个是数学乘法分配律逆运算,需要巧算的过程,
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/11 22:22:10
数学乘法分配律(-1/30)÷(2/3-1/10+1/6-2/5)计算怎样巧算?再计算:(-1÷42)÷(1÷6-3÷14+2÷3-2÷7),这个是数学乘法分配律逆运算,需要巧算的过程,
数学乘法分配律
(-1/30)÷(2/3-1/10+1/6-2/5)计算怎样巧算?再计算:(-1÷42)÷(1÷6-3÷14+2÷3-2÷7),
这个是数学乘法分配律逆运算,需要巧算的过程,
数学乘法分配律(-1/30)÷(2/3-1/10+1/6-2/5)计算怎样巧算?再计算:(-1÷42)÷(1÷6-3÷14+2÷3-2÷7),这个是数学乘法分配律逆运算,需要巧算的过程,
① 原式=(-1/30)÷(2/3-1/10+1/6-2/5)
=(-1/30)/[(2/3+1/6)-(1/10+2/5)]
=(-1/30)/(1/3)
=-1/10
② 原式= (-1÷42)÷(1÷6-3÷14+2÷3-2÷7)
=(-1/42)/[(1/6+2/3)-(3/14+2/7)]
=(-1/42)/(1/3)
=-1/14
(-1/30)÷(2/3-1/10+1/6-2/5)
=(-1/30)÷[(4/6+1/6)-(4/10+1/10)]
=(-1/30)÷[50/60-30/60]
=(-1/30)÷[1/3)
=-1/10
(-1÷42)÷(1÷6-3÷14+2÷3-2÷7)
通分:
(-1/30)÷(2/3-1/10+1/6-2/5)
=(-1/30)/[(2/3+1/6)-(1/10+2/5)]
=(-1/30)/(1/3)
=-1/10
(-1÷42)÷(1÷6-3÷14+2÷3-2÷7)
=(-1/42)/[(1/6+2/3)-(3/14+2/7)]
=(-1/42)/(1/3)
=-1/14
十分之一,十四分之一
a(b+c)=ab+ac
(-1/30)÷(2/3-1/10+1/6-2/5)=(-1)÷(20-3+5-12)=-1/10 同时乘30
第二题也一样不是巧算,你知道怎么巧算吗?不是巧算,你知道怎么巧算吗?(-1/30)÷(2/3-1/10+1/6-2/5)=(-1/30)÷(1/30)(20-3+5-12)=(-1)÷(10)=-1/10
这不是逆运算吗其实我是知道怎么样...
全部展开
(-1/30)÷(2/3-1/10+1/6-2/5)=(-1)÷(20-3+5-12)=-1/10 同时乘30
第二题也一样
收起
前一题被除数和除数同乘以30;第二题被除数何除数同乘以42就行。按运算顺序需先通分,这就比较繁,同乘以30,运用乘法分配率,就无需通分。
(-1/30)÷(2/3-1/10+1/6-2/5)
=(-1/30)÷ (2/3+1/6-1/10-2/5)
=(-1/30)÷(5/6 -1/2)
=(-1/30)÷1/3
=-1/30×3
= -1/10
(-1÷42)÷(1÷6-3÷14+2÷3-2÷7)
= -1/42÷ (1/6+2/3-3/14-2/7)
= -1/42...
全部展开
(-1/30)÷(2/3-1/10+1/6-2/5)
=(-1/30)÷ (2/3+1/6-1/10-2/5)
=(-1/30)÷(5/6 -1/2)
=(-1/30)÷1/3
=-1/30×3
= -1/10
(-1÷42)÷(1÷6-3÷14+2÷3-2÷7)
= -1/42÷ (1/6+2/3-3/14-2/7)
= -1/42÷(5/6-1/2)
= -1/42÷1/3
= -1/42×3
= -1/14
收起