题目内容
| 脱式计算,能简算的就简算 (
|
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|
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分析:①③应用乘法分配律简便计算,②④按分数、整数四则混合运算顺序计算.
解答:解:①(
+
+
)×12
=
×12+
×12+
×12
=6+2+1
=9;
②
+(
-
)÷
=
+
×12
=
+
=
;
③
÷9+
×
=
×(
+
)
=
×1
=
;
④
÷(1-
)×
=
×6×
=
.
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 12 |
=
| 1 |
| 2 |
| 1 |
| 6 |
| 1 |
| 12 |
=6+2+1
=9;
②
| 15 |
| 16 |
| 7 |
| 16 |
| 1 |
| 4 |
| 1 |
| 12 |
=
| 15 |
| 16 |
| 3 |
| 16 |
=
| 15 |
| 16 |
| 36 |
| 16 |
=
| 51 |
| 16 |
③
| 18 |
| 19 |
| 1 |
| 19 |
| 1 |
| 9 |
=
| 1 |
| 9 |
| 18 |
| 19 |
| 1 |
| 19 |
=
| 1 |
| 9 |
=
| 1 |
| 9 |
④
| 1 |
| 3 |
| 5 |
| 6 |
| 3 |
| 4 |
=
| 1 |
| 3 |
| 3 |
| 4 |
=
| 3 |
| 2 |
点评:此题主要考查分数、整数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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