Teacher Li brought 800 yuan to buy school supplies, bought 16 boxes of pens, and left 80 yuan, how much is each box of pens?
李老师带800元买学习用品，买了16盒钢笔，还剩下80元，每盒钢笔多少钱？
<gadget id="calculator">800 - 80</gadget>
<output>720</output>

<gadget id="calculator">720 / 16</gadget>
<output>45</output>

<result>45</result>