题目内容
计算下面各题,能简便的要用简便方法计算.
12.18-(3.18+0.64)
×
+
÷5
(
-
)÷
×5
÷[(
-
]×
].
12.18-(3.18+0.64)
7 |
11 |
4 |
5 |
7 |
11 |
(
5 |
4 |
21 |
20 |
1 |
15 |
5 |
9 |
3 |
7 |
1 |
14 |
7 |
9 |
考点:分数的四则混合运算,运算定律与简便运算,小数四则混合运算
专题:运算顺序及法则,运算定律及简算
分析:(1)先去括号,再进行计算;
(2)把除以5化成乘以
,再运用乘法的分配律进行简算;
(3)先算小括号里面的减法,再算括号外的除法,最后算乘法;
(4)先算小括号里的减法,再算中括号里的乘法,最后算括号外的除法.
(2)把除以5化成乘以
1 |
5 |
(3)先算小括号里面的减法,再算括号外的除法,最后算乘法;
(4)先算小括号里的减法,再算中括号里的乘法,最后算括号外的除法.
解答:
解:(1)12.18-(3.18+0.64)
=12.18-3.18-0.64
=9-0.64
=8.36;
(2)
×
+
÷5
=
×(
+
)
=
×1
=
;
(3)(
-
)÷
×5
=
×15×5
=3×5
=15;
(4)
÷[(
-
)×
]
=
÷[
×
]
=
÷
=
.
=12.18-3.18-0.64
=9-0.64
=8.36;
(2)
7 |
11 |
4 |
5 |
7 |
11 |
=
7 |
11 |
4 |
5 |
1 |
5 |
=
7 |
11 |
=
7 |
11 |
(3)(
5 |
4 |
21 |
20 |
1 |
15 |
=
1 |
5 |
=3×5
=15;
(4)
5 |
9 |
3 |
7 |
1 |
14 |
7 |
9 |
=
5 |
9 |
5 |
14 |
7 |
9 |
=
5 |
9 |
5 |
6 |
=
2 |
3 |
点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.
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