题目内容
下面等式不成立的是( )
分析:对选项中的算式按照运算顺序进行计算,找出左右两边不相等的算式即可.
解答:解:A,
-
+
,
=
+
,
=
;
+
-
,
=1-
=
;
两个算式的运算结果相等,等式成立;
B,
÷
×
,
=
×
,
=
;
×
÷
,
=1÷
,
=
;
两个算式的运算结果相等,等式成立;
C,
+
÷
+
,
=
+
+
,
=
+
,
=
;
(
+
)÷(
+
),
=1÷1,
=1;
≠1;两个算式的运算结果不相等,等式不成立;
故选:C.
| 9 |
| 10 |
| 3 |
| 7 |
| 1 |
| 10 |
=
| 33 |
| 70 |
| 1 |
| 10 |
=
| 4 |
| 7 |
| 9 |
| 10 |
| 1 |
| 10 |
| 3 |
| 7 |
=1-
| 3 |
| 7 |
=
| 4 |
| 7 |
两个算式的运算结果相等,等式成立;
B,
| 7 |
| 8 |
| 2 |
| 5 |
| 8 |
| 7 |
=
| 35 |
| 16 |
| 8 |
| 7 |
=
| 5 |
| 2 |
| 7 |
| 8 |
| 8 |
| 7 |
| 2 |
| 5 |
=1÷
| 2 |
| 5 |
=
| 5 |
| 2 |
两个算式的运算结果相等,等式成立;
C,
| 1 |
| 4 |
| 3 |
| 4 |
| 2 |
| 3 |
| 1 |
| 3 |
=
| 1 |
| 4 |
| 9 |
| 8 |
| 1 |
| 3 |
=
| 11 |
| 8 |
| 1 |
| 3 |
=
| 41 |
| 24 |
(
| 1 |
| 4 |
| 3 |
| 4 |
| 2 |
| 3 |
| 1 |
| 3 |
=1÷1,
=1;
| 41 |
| 24 |
故选:C.
点评:本题主要考查了对运算定律等简便方法的运用,要注意分析,不要错用运算定律.
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