(1)=(2)=(3)31.4+15.19+20.6+32.81=(4)=(5)=(6)=(7)9+19+199+1999=(8)0.9+0.99+0.999+0.1

发布时间:2020-08-10 07:19:42

(1)=
(2)=
(3)31.4+15.19+20.6+32.81=
(4)=
(5)=
(6)=
(7)9+19+199+1999=
(8)0.9+0.99+0.999+0.111=

网友回答

解:
(1),
=(14+1)×,
=14×+1×,
=1+,
=1;

(2),
=8--6,
=8-6-,
=2-,
=1;

(3)31.4+15.19+20.6+32.81,
=(31.4+20.6)+(15.19+32.81),
=52+48,
=100;

(4),
=()-(),
=1-1,
=;

(5),
=()-(),
=89-46,
=42;

(6),
=[()+()]÷5,
=[5+4]÷5,
=9÷5,
=1.8;

(7)9+19+199+1999,
=(1+1+1+6)+19+199+1999,
=(1+19)+(1+199)+(1+1999)+6,
=20+200+2000+6,
=2220+6,
=2226;

(8)0.9+0.99+0.999+0.111,
=0.9+0.99+0.999+(0.1+0.01+0.001),
=(0.9+0.1)+(0.99+0.01)+(0.999+0.001),
=1+1+1,
=3.
解析分析:(1)15=14+1,然后再根据乘法分配律进行简算;
(2)根据减法的性质进行简算;
(3)根据加法交换律和结合律进行简算;
(4)根据加法交换律和结合律进行简算;
(5)根据加法交换律和结合律进行简算;
(6)根据加法交换律和结合律进行简算;
(7)9=1+1+1+6,然后再根据加法交换律和结合律进行简算;
(8)0.111=0.1+0.01+0.001,然后再根据加法交换律和结合律进行简算.

点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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