Select 12 good students from 8 classes, each class has at least 1 student, how many selection methods are there?
从8个班选12个三好学生，每班至少1名，共有多少种选法．
<gadget id="calculator">8 * 7</gadget>
<output>56</output>

<gadget id="calculator">56 / 2</gadget>
<output>28</output>

<gadget id="calculator">28 + 56</gadget>
<output>84</output>

<gadget id="calculator">8 * 7 * 6</gadget>
<output>336</output>

<gadget id="calculator">1 * 2 * 3</gadget>
<output>6</output>

<gadget id="calculator">336 / 6</gadget>
<output>56</output>

<gadget id="calculator">3 * 56</gadget>
<output>168</output>

<gadget id="calculator">8 * 7 * 6 * 5</gadget>
<output>1_680</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">1 * 2 * 3 * 4</gadget>
<output>24</output>

<gadget id="calculator">1_680 / 24</gadget>
<output>70</output>

<gadget id="calculator">8 + 84 + 168 + 70</gadget>
<output>330</output>

<result>330</result>