45 students go to the garden, each of them wants to drink 1 bottle of mineral water, buy 4 bottles in the store and get 1 free, then they only need to pay for how many bottles they buy.
45名学生去游园，他们每人想喝1瓶矿泉水，商店买4瓶送1瓶，那么他们只需要付钱买的有多少瓶．
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">45 / 5</gadget>
<output>9</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>