The father said to his son, "When I was your age, you were only 4 years old; when you were my age, I was 79 years old." How old is the father now.
父亲对儿子说"我像你这么大时，你才4岁；当你像我这么大时，我就79岁啦．"现在父亲的年龄是多少岁．
<gadget id="calculator">79 - 4</gadget>
<output>75</output>

<gadget id="calculator">1 + 1 + 1</gadget>
<output>3</output>

<gadget id="calculator">75 / 3</gadget>
<output>25</output>

<gadget id="calculator">79 - 25</gadget>
<output>54</output>

<result>54</result>