It is obvious that you want to choose 3 books from the 7 books A, B, C, D, E, F, and G to lend to a good friend. How many choices are there?
明明要从A、B、C、D、E、F、G这7本书中选3本借给好朋友，共有多少种选法？
<gadget id="calculator">7 * 6 * 5</gadget>
<output>210</output>

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

<gadget id="calculator">210 / 6</gadget>
<output>35</output>

<result>35</result>