Momofuku Supermarket held a Coke "buy 3 get 1 free" event. There are 56 students in the third grade. If each person drinks a bottle of Coke, how many bottles do they need to buy?
百福超市举行可乐"买3赠1"的活动．三年级共有56人，每人喝一瓶可乐，只需要买多少瓶？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">56 / 4</gadget>
<output>14</output>

<gadget id="calculator">14 * 3</gadget>
<output>42</output>

<result>42</result>