Mom brought 100 yuan, bought a schoolbag and spent 72 yuan, and the rest of the money bought 3.5 yuan a pen, how many pens can I buy?
妈妈带了100元钱，买一个书包共用去72元，剩下的钱买3.5元一支的钢笔，可以买多少支？
<gadget id="calculator">100 - 72</gadget>
<output>28</output>

<gadget id="calculator">28 / 3.5</gadget>
<output>8</output>

<result>8</result>