Xiaohua is 12 years old this year, and his mother is 36 years old. When his mother was, she was exactly five times Xiaohua's age.
小华今年12岁，妈妈36岁，他的妈妈多少岁时，年龄正好是小华的5倍．
<gadget id="calculator">36 - 12</gadget>
<output>24</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<result>30</result>