The younger brother is 4 years old this year, and the older sister is 20 years old this year. After 4 years, the elder sister will be older than the younger brother by how many times.
弟弟今年4岁，姐姐今年20岁，4年后姐姐比弟弟的年龄大多少倍．
<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">4 + 4</gadget>
<output>8</output>

<gadget id="calculator">16 / 8</gadget>
<output>2</output>

<result>2</result>