Dad's age is grandpa's (3/5), and my age happens to be dad's (1/4), I am 12 years old this year, how old is grandpa?
爸爸年龄是爷爷的(3/5)，而我的年龄恰好是爸爸的(1/4)，今年我12岁，爷爷几岁？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">12 / (1/4) / (3/5)</gadget>
<output>80</output>

<result>80</result>