Teacher Wang spent 180 yuan to buy 5 boxes of milk, each box has 9 bottles, how much is each bottle?
王老师花180元买了5箱牛奶，每箱有9瓶，每瓶多少元？
<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">180 / 45</gadget>
<output>4</output>

<result>4</result>