The grandfather is 72 years old this year, and the granddaughter is 12 years old this year. In a few years, the grandfather will be 5 times the age of the granddaughter.
爷爷今年72岁，孙女今年12岁，再过多少年，爷爷年龄是孙女的5倍．
<gadget id="calculator">72 - 12</gadget>
<output>60</output>

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

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">15 - 12</gadget>
<output>3</output>

<result>3</result>