题目内容
下面各题,怎样简便就怎样算
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(
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分析:(1)先算乘法,再算加法;
(2)先算乘法,再算减法;
(3)(4)(5)约分计算;
(6)(8)运用乘法分配律简算;
(7)把86看作(85+1),运用乘法分配律简算.
(2)先算乘法,再算减法;
(3)(4)(5)约分计算;
(6)(8)运用乘法分配律简算;
(7)把86看作(85+1),运用乘法分配律简算.
解答:解:(1)
+
×
,
=
+
,
=
;
(2)
×
-
,
=
-
,
=
;
(3)
×
×
=
;
(4)
×
×17=5;
(5)
×
×
=
;
(6)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(7)
×86,
=
×(85+1),
=
×85+
,
=3
;
(8)(
+
)×54,
=
×54+
×54,
=42+10,
=52.
| 2 |
| 3 |
| 4 |
| 15 |
| 5 |
| 8 |
=
| 2 |
| 3 |
| 1 |
| 6 |
=
| 5 |
| 6 |
(2)
| 5 |
| 16 |
| 8 |
| 15 |
| 1 |
| 18 |
=
| 1 |
| 6 |
| 1 |
| 18 |
=
| 1 |
| 9 |
(3)
| 5 |
| 7 |
| 4 |
| 15 |
| 7 |
| 8 |
| 1 |
| 6 |
(4)
| 12 |
| 17 |
| 5 |
| 12 |
(5)
| 1 |
| 6 |
| 3 |
| 8 |
| 6 |
| 11 |
| 3 |
| 88 |
(6)
| 5 |
| 6 |
| 7 |
| 8 |
| 5 |
| 6 |
| 1 |
| 8 |
=
| 5 |
| 6 |
| 7 |
| 8 |
| 1 |
| 8 |
=
| 5 |
| 6 |
=
| 5 |
| 6 |
(7)
| 3 |
| 85 |
=
| 3 |
| 85 |
=
| 3 |
| 85 |
| 3 |
| 85 |
=3
| 3 |
| 85 |
(8)(
| 7 |
| 9 |
| 5 |
| 27 |
=
| 7 |
| 9 |
| 5 |
| 27 |
=42+10,
=52.
点评:此题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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