Xiaoyun buys 3 volleyballs, pays 100 yuan, and gets back 7 yuan. How much is each volleyball?
小芸买3个排球，付出100元，找回7元，每个排球多少元？
<gadget id="calculator">100 - 7</gadget>
<output>93</output>

<gadget id="calculator">93 / 3</gadget>
<output>31</output>

<result>31</result>