题目内容
(1+
)+(2+
)+(3+
)+…+(97+
).
| 1 |
| 97 |
| 2 |
| 97 |
| 3 |
| 97 |
| 97 |
| 97 |
(1+
)+(2+
)+(3+
)+…+(97+
)
=(1+
)+2×(1+
)+3×(1+
)+…97×(1+
),
=(1+2+3…+97)×(1+
),
=
×(1+
)
=
×1+
×
=4753+49
=4802
| 1 |
| 97 |
| 2 |
| 97 |
| 3 |
| 97 |
| 97 |
| 97 |
=(1+
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
| 1 |
| 97 |
=(1+2+3…+97)×(1+
| 1 |
| 97 |
=
| 97×(97+1) |
| 2 |
| 1 |
| 97 |
=
| 97×(97+1) |
| 2 |
| 97×(97+1) |
| 2 |
| 1 |
| 97 |
=4753+49
=4802
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