This year Xiaohong's age is grandpa's (4/15). Five years ago, Xiaohong's age was grandpa's (1/5). How old is grandpa this year?
今年小红的年龄是爷爷的(4/15)，5年前，小红的年龄是爷爷的(1/5)，爷爷今年多少岁？
<gadget id="calculator">15 - 4</gadget>
<output>11</output>

<gadget id="calculator">4 / 11</gadget>
<output>4/11 = around 0.363636</output>

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

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(4/11) - (1/4)</gadget>
<output>5/44 = around 0.113636</output>

<gadget id="calculator">5 / (5/44)</gadget>
<output>44</output>

<gadget id="calculator">44 / 11</gadget>
<output>4</output>

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

<result>60</result>