题目内容
神机妙算(写出简算过程)
2005×
(3-
+
)×5×7
999
+99
+9
+
.
2005×
| 2003 |
| 2004 |
(3-
| 1 |
| 5 |
| 2 |
| 7 |
999
| 8 |
| 9 |
| 8 |
| 9 |
| 8 |
| 9 |
| 1 |
| 3 |
(1)2005×
,
=(2004+1)×
,
=2004×
+
×1,
=2003+
,
=2003
;
(2)(3-
+
)×5×7,
=(3-
+
)×35,
=35×3-35×
+35×
,
=105-7+10,
=98+10,
=108;
(3)999
+99
+9
+
,
=999
+99
+9
+
,
=(999
+
)+(99
+
)+(9
+
),
=1000+100+10,
=1110.
| 2003 |
| 2004 |
=(2004+1)×
| 2003 |
| 2004 |
=2004×
| 2003 |
| 2004 |
| 2003 |
| 2004 |
=2003+
| 2003 |
| 2004 |
=2003
| 2003 |
| 2004 |
(2)(3-
| 1 |
| 5 |
| 2 |
| 7 |
=(3-
| 1 |
| 5 |
| 2 |
| 7 |
=35×3-35×
| 1 |
| 5 |
| 2 |
| 7 |
=105-7+10,
=98+10,
=108;
(3)999
| 8 |
| 9 |
| 8 |
| 9 |
| 8 |
| 9 |
| 1 |
| 3 |
=999
| 8 |
| 9 |
| 8 |
| 9 |
| 8 |
| 9 |
| 3 |
| 9 |
=(999
| 8 |
| 9 |
| 1 |
| 9 |
| 8 |
| 9 |
| 1 |
| 9 |
| 8 |
| 9 |
| 1 |
| 9 |
=1000+100+10,
=1110.
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