There is a promotion in the supermarket. Soup bowls are 16 yuan each. Buy 3 and get one free. Grandma Liu bought 3 soup bowls at a time. How much is each cheaper?
超市搞促销活动，汤碗16元一个，买3个送一个，刘奶奶一次买了3个汤碗，每个便宜多少钱？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">16 * (3/4)</gadget>
<output>12</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<result>4</result>