Mingming is 12 years old this year, and Qiangqiang is 7 years old this year. When the sum of their ages is 45 years old, how old are they?
明明今年12岁，强强今年7岁，当两人的年龄和是45岁时，两人各多少岁？
<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<gadget id="calculator">45 - 5</gadget>
<output>40</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">45 - 20</gadget>
<output>25</output>

<result>25</result>