题目内容
计算下面各题,能简便的要简便计算.
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[4-(
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分析:(1)(5)(7)先分子和分母交叉约分,再计算;
(2)(3)(6)运用或逆用乘法分配律简算;
(4)按照先算乘法,再算加法的顺序计算;
(8)先算小括号里面的减法,再算中括号里面的减法,最后算括号外面的乘法.
(2)(3)(6)运用或逆用乘法分配律简算;
(4)按照先算乘法,再算加法的顺序计算;
(8)先算小括号里面的减法,再算中括号里面的减法,最后算括号外面的乘法.
解答:解:(1)
×
×
,
=
;
(2)(
+
)×27,
=
×27+
×27,
=24+4,
=28;
(3)
×6+
×6,
=(
+
)×6,
=6;
(4)
+
×
,
=
+
,
=
;
(5)
×
×
,
=
;
(6)(
+
)×36,
=
×36+
×36,
=9+8,
=17;
(7)
×
×50,
=
;
(8)[4-(
-
)]×
,
=[4-
]×
,
=
×
,
=
.
| 7 |
| 11 |
| 5 |
| 8 |
| 11 |
| 10 |
=
| 7 |
| 16 |
(2)(
| 8 |
| 9 |
| 4 |
| 27 |
=
| 8 |
| 9 |
| 4 |
| 27 |
=24+4,
=28;
(3)
| 7 |
| 12 |
| 5 |
| 12 |
=(
| 7 |
| 12 |
| 5 |
| 12 |
=6;
(4)
| 4 |
| 11 |
| 2 |
| 11 |
| 11 |
| 6 |
=
| 4 |
| 11 |
| 1 |
| 3 |
=
| 23 |
| 33 |
(5)
| 5 |
| 18 |
| 1 |
| 4 |
| 9 |
| 10 |
=
| 1 |
| 16 |
(6)(
| 1 |
| 4 |
| 2 |
| 9 |
=
| 1 |
| 4 |
| 2 |
| 9 |
=9+8,
=17;
(7)
| 19 |
| 100 |
| 3 |
| 8 |
=
| 57 |
| 16 |
(8)[4-(
| 3 |
| 4 |
| 3 |
| 8 |
| 4 |
| 29 |
=[4-
| 3 |
| 8 |
| 4 |
| 29 |
=
| 29 |
| 8 |
| 4 |
| 29 |
=
| 1 |
| 2 |
点评:此题主要考查分数四则混合运算,在计算时要注意运算顺序和运算法则,根据数据的特点能简算的要灵活运用所学的运算律进行简便计算.
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