题目内容
(2012?明光市)
下列各题怎样简便就怎样计算. 0.125×25×32 |
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(
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分析:(1)0.125×25×32,把32分解为:4×8,然后运用乘法交换律和结合律进行简算;
(2)
÷
×
,根据分数乘法、除法计算法则,把除数转化为乘它的倒数,然后按照分数乘法的计算法则进行计算;
(3)
-(
+
),根据减法的运算性质:a-(b+c)=a-b-c,据此进行简算;
(4)(
+
-
)×20,运用乘法分配律进行简算.
(2)
3 |
5 |
5 |
6 |
5 |
18 |
(3)
20 |
17 |
3 |
17 |
2 |
3 |
(4)(
1 |
4 |
4 |
5 |
7 |
10 |
解答:解:(1)0.125×25×32,
=(0.125×8)×(4×25),
=1×100,
=100;
(2)
÷
×
,
=
×
×
,
=
;
(3)
-(
+
),
=
-
-
,
=1-
,
=
;
(4)(
+
-
)×20,
=
×20+
×20-
×20,
=5+16-14,
=7.
=(0.125×8)×(4×25),
=1×100,
=100;
(2)
3 |
5 |
5 |
6 |
5 |
18 |
=
3 |
5 |
6 |
5 |
5 |
18 |
=
1 |
5 |
(3)
20 |
17 |
3 |
17 |
2 |
3 |
=
20 |
17 |
3 |
17 |
2 |
3 |
=1-
2 |
3 |
=
1 |
3 |
(4)(
1 |
4 |
4 |
5 |
7 |
10 |
=
1 |
4 |
4 |
5 |
7 |
10 |
=5+16-14,
=7.
点评:此题考查的目的是使学生牢固掌握分数、小数四则混合运算的顺序和它们的计算法则,并且能够灵活运用运算定律、运算性质进行简便计算.
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