The teacher said to the students: When I was your age, you were 3 years old. I was 39 when you were my age, how old is the teacher now?
老师对学生说：当我像你这么大时，你3岁．当你像我这么大时，我39岁，老师现在几岁？
<gadget id="calculator">39 - 3</gadget>
<output>36</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">36 / 3</gadget>
<output>12</output>

<gadget id="calculator">2 * 12</gadget>
<output>24</output>

<gadget id="calculator">24 + 3</gadget>
<output>27</output>

<result>27</result>