题目内容
计算:51
÷
+71
÷
-91
×
.
| 2 |
| 3 |
| 5 |
| 3 |
| 3 |
| 4 |
| 7 |
| 4 |
| 4 |
| 5 |
| 5 |
| 9 |
51
÷
+71
÷
-91
×
,
=51
×
+71
×
-91
×
,
=(50+
)×
+(70+
)×
-(90+
)×
,
=[50×
+
×
]+[70×
+
×
]-[90×
+
×
],
=[30+1]+[40+1]-[50+1],
=31+41-51,
=72-51,
=21.
| 2 |
| 3 |
| 5 |
| 3 |
| 3 |
| 4 |
| 7 |
| 4 |
| 4 |
| 5 |
| 5 |
| 9 |
=51
| 2 |
| 3 |
| 3 |
| 5 |
| 3 |
| 4 |
| 4 |
| 7 |
| 4 |
| 5 |
| 5 |
| 9 |
=(50+
| 5 |
| 3 |
| 3 |
| 5 |
| 7 |
| 4 |
| 4 |
| 7 |
| 9 |
| 5 |
| 5 |
| 9 |
=[50×
| 3 |
| 5 |
| 5 |
| 3 |
| 3 |
| 5 |
| 4 |
| 7 |
| 7 |
| 4 |
| 4 |
| 7 |
| 5 |
| 9 |
| 9 |
| 5 |
| 5 |
| 9 |
=[30+1]+[40+1]-[50+1],
=31+41-51,
=72-51,
=21.
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