Xiao Ming went to buy soda, the salesperson said: "Every 3 empty bottles can be exchanged for 1 bottle of soda, Xiao Ming bought 10 bottles of soda, how many bottles of soda can be exchanged in total?
小明去买汽水，售货员说："每3个空瓶可换1瓶汽水，小明买了10瓶汽水，一共可换多少瓶汽水？
<gadget id="calculator">3 + 1 + 1</gadget>
<output>5</output>

<result>5</result>