Xiaohua is 12 years old this year, and his mother is 48 years old this year. How many years ago, her mother was five times Xiaohua's age.
小华今年12岁，他妈妈今年48岁，多少年以前妈妈的年龄是小华的5倍．
<gadget id="calculator">48 - 12</gadget>
<output>36</output>

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

<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<result>3</result>