Dad is 58 years old this year, 7 years more than 3 times Xiao Ming's age, how old is Xiao Ming this year?
爸爸今年58岁，比小明年龄的3倍还多7岁，小明今年多少岁．
<gadget id="calculator">58 - 7</gadget>
<output>51</output>

<gadget id="calculator">51 / 3</gadget>
<output>17</output>

<result>17</result>