题目内容
计算下面各题(能简便的要简便计算)
|
15-5÷12-
|
1-
| ||||||||||||||||||||
|
|
|
分析:(1)根据乘法的意义,写成乘法算式计算;
(2)先算除法,再运用减法的性质简算;
(3)按照从左到右的顺序计算;
(4)先去掉括号,再计算;
(5)运用加法交换律和加法结合律简算;
(6)先算小括号里面的减法,再算括号外的加法.
(2)先算除法,再运用减法的性质简算;
(3)按照从左到右的顺序计算;
(4)先去掉括号,再计算;
(5)运用加法交换律和加法结合律简算;
(6)先算小括号里面的减法,再算括号外的加法.
解答:解:(1)
+
+
,
=
×3,
=
;
(2)15-5÷12-
,
=15-
-
,
=15-(
+
),
=15-1,
=14;
(3)1-
+
,
=
+
,
=
;
(4)
-(
-
),
=
-
+
,
=
+
,
=
;
(5)
+
+
+
,
=(
+
)+(
+
),
=
+1,
=1
;
(6)
+(
-
),
=
+
,
=
.
| 5 |
| 13 |
| 5 |
| 13 |
| 5 |
| 13 |
=
| 5 |
| 13 |
=
| 15 |
| 13 |
(2)15-5÷12-
| 7 |
| 12 |
=15-
| 5 |
| 12 |
| 7 |
| 12 |
=15-(
| 5 |
| 12 |
| 7 |
| 12 |
=15-1,
=14;
(3)1-
| 1 |
| 6 |
| 1 |
| 3 |
=
| 5 |
| 6 |
| 1 |
| 3 |
=
| 7 |
| 6 |
(4)
| 5 |
| 7 |
| 4 |
| 7 |
| 10 |
| 21 |
=
| 5 |
| 7 |
| 4 |
| 7 |
| 10 |
| 21 |
=
| 1 |
| 7 |
| 10 |
| 21 |
=
| 13 |
| 21 |
(5)
| 4 |
| 11 |
| 3 |
| 5 |
| 6 |
| 11 |
| 2 |
| 5 |
=(
| 4 |
| 11 |
| 6 |
| 11 |
| 3 |
| 5 |
| 2 |
| 5 |
=
| 10 |
| 11 |
=1
| 10 |
| 11 |
(6)
| 7 |
| 36 |
| 11 |
| 12 |
| 1 |
| 2 |
=
| 7 |
| 36 |
| 5 |
| 12 |
=
| 11 |
| 18 |
点评:此题主要考查分数的加减混合运算的运算顺序,以及应用运算定律进行简便计算的能力.
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