题目内容
脱式计算.
(
|
|
(
|
|
分析:(1)先算括号内的,再算括号外的;
(2)把除法改为乘法,运用乘法分配律简算;
(3)两个括号同时计算,再算除法;
(4)先算小括号内的,再算中括号内的,最后算括号外的.
(2)把除法改为乘法,运用乘法分配律简算;
(3)两个括号同时计算,再算除法;
(4)先算小括号内的,再算中括号内的,最后算括号外的.
解答:解:(1)(
+
)÷
,
=
×
,
=
;
(2)
÷6+
×
,
=
×
+
×
,
=(
+
)×
,
=
;
(3)(
+
)÷(
-
),
=
÷
,
=
×
,
=
;
(4)
÷[(
-
)×15],
=
÷[
×15],
=
÷
,
=
×
,
=
.
| 3 |
| 10 |
| 1 |
| 4 |
| 2 |
| 5 |
=
| 11 |
| 20 |
| 5 |
| 2 |
=
| 11 |
| 8 |
(2)
| 4 |
| 7 |
| 3 |
| 7 |
| 1 |
| 6 |
=
| 4 |
| 7 |
| 1 |
| 6 |
| 3 |
| 7 |
| 1 |
| 6 |
=(
| 4 |
| 7 |
| 3 |
| 7 |
| 1 |
| 6 |
=
| 1 |
| 6 |
(3)(
| 5 |
| 6 |
| 3 |
| 8 |
| 5 |
| 6 |
| 3 |
| 8 |
=
| 29 |
| 24 |
| 11 |
| 24 |
=
| 29 |
| 24 |
| 24 |
| 11 |
=
| 29 |
| 11 |
(4)
| 2 |
| 3 |
| 4 |
| 5 |
| 1 |
| 4 |
=
| 2 |
| 3 |
| 11 |
| 20 |
=
| 2 |
| 3 |
| 33 |
| 4 |
=
| 2 |
| 3 |
| 4 |
| 33 |
=
| 8 |
| 99 |
点评:考查了分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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