Kobayashi is 9 years old this year, and he is 30 years younger than his father. How old was Dad 5 years ago?
小林今年9岁，他比爸爸小30岁．5年前爸爸多少岁．
<gadget id="calculator">30 - 5</gadget>
<output>25</output>

<gadget id="calculator">9 + 25</gadget>
<output>34</output>

<result>34</result>