In Dongkang Supermarket’s anniversary celebration, a certain brand of soap held a promotion, buy three and get one free. If you buy 4 pieces of soap, the actual price will be sold at the original price.
东康超市周年店庆，某品牌香皂举行促销活动，买三赠一，若买4块香皂，则实际价格是按原价的多少出售．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

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

<result>3/4 = around 0.75</result>