题目内容
怎样简便怎样算.
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[1-(
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7
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考点:分数的四则混合运算,分数的简便计算
专题:运算顺序及法则
分析:(1)按照从左到右顺序计算解答,
(2)按照先算括号里面的,再算括号外面的顺序计算解答,
(3)(5)(6)(7)(9)运用乘法分配律解答,
(4)(10)(12)按照先算小括号里面的,再算中括号里面的,最后算括号外面的顺序计算解答,
(8)按照先同时计算第二级运算,再算第一级运算顺序计算解答,
(11)按照先算除法,再运用加法结合律解答.
(2)按照先算括号里面的,再算括号外面的顺序计算解答,
(3)(5)(6)(7)(9)运用乘法分配律解答,
(4)(10)(12)按照先算小括号里面的,再算中括号里面的,最后算括号外面的顺序计算解答,
(8)按照先同时计算第二级运算,再算第一级运算顺序计算解答,
(11)按照先算除法,再运用加法结合律解答.
解答:
解:(1)
×
÷
=
÷
=1;
(2)
÷(
+
)
=
÷
=
;
(3)
×7+
×11
=
×(7+11)
=
×18
=10;
(4)[1-(
+
)]÷
=[1-
]÷
=
÷
=1
;
(5)
×99+
=
×(99+1)
=
×100
=16;
(6)
×
+
÷1
=(
+
)×
=1×
=
;
(7)
÷7+
×
=
×(
+
)
=
×
=
;
(8)
×
+
÷
=
+2
=2
;
(9)
×24+
×24+
×24
=12+16+18
=46;
(10)7
÷[1
÷(4
-
)]
=7
÷[1
÷4
]
=7
÷
=24
;
(11)
+
÷
+
=
+(
+
)
=
+1
=1
;
(12)
÷[
-(
-
)]
=
÷[
-
]
=
÷
=
.
| 3 |
| 4 |
| 6 |
| 13 |
| 9 |
| 26 |
=
| 9 |
| 26 |
| 9 |
| 26 |
=1;
(2)
| 4 |
| 9 |
| 1 |
| 3 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 2 |
| 3 |
=
| 2 |
| 3 |
(3)
| 5 |
| 9 |
| 5 |
| 9 |
=
| 5 |
| 9 |
=
| 5 |
| 9 |
=10;
(4)[1-(
| 1 |
| 4 |
| 3 |
| 8 |
| 1 |
| 4 |
=[1-
| 5 |
| 8 |
| 1 |
| 4 |
=
| 3 |
| 8 |
| 1 |
| 4 |
=1
| 1 |
| 2 |
(5)
| 4 |
| 25 |
| 4 |
| 25 |
=
| 4 |
| 25 |
=
| 4 |
| 25 |
=16;
(6)
| 3 |
| 5 |
| 2 |
| 3 |
| 2 |
| 5 |
| 1 |
| 2 |
=(
| 3 |
| 5 |
| 2 |
| 5 |
| 2 |
| 3 |
=1×
| 2 |
| 3 |
=
| 2 |
| 3 |
(7)
| 8 |
| 13 |
| 1 |
| 7 |
| 6 |
| 13 |
=
| 1 |
| 7 |
| 8 |
| 13 |
| 6 |
| 13 |
=
| 1 |
| 7 |
| 14 |
| 13 |
=
| 2 |
| 13 |
(8)
| 1 |
| 2 |
| 2 |
| 5 |
| 9 |
| 10 |
| 9 |
| 20 |
=
| 1 |
| 5 |
=2
| 1 |
| 5 |
(9)
| 1 |
| 2 |
| 2 |
| 3 |
| 3 |
| 4 |
=12+16+18
=46;
(10)7
| 1 |
| 3 |
| 1 |
| 4 |
| 2 |
| 3 |
| 1 |
| 2 |
=7
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 6 |
=7
| 1 |
| 3 |
| 3 |
| 10 |
=24
| 4 |
| 9 |
(11)
| 2 |
| 9 |
| 1 |
| 2 |
| 4 |
| 5 |
| 3 |
| 8 |
=
| 2 |
| 9 |
| 5 |
| 8 |
| 3 |
| 8 |
=
| 2 |
| 9 |
=1
| 2 |
| 9 |
(12)
| 9 |
| 32 |
| 3 |
| 4 |
| 7 |
| 16 |
| 1 |
| 4 |
=
| 9 |
| 32 |
| 3 |
| 4 |
| 3 |
| 16 |
=
| 9 |
| 32 |
| 9 |
| 16 |
=
| 1 |
| 2 |
点评:(1)依据四则运算计算方法正确进行计算,(2)正确运用简便方法解决问题,是本题考查知识点.
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