The grandfather is 72 years old this year, the age of the father is that of the grandfather (5/8), and the age of the son is that of the father (1/3). How old is your son?
爷爷今年72岁，爸爸的年龄是爷爷的(5/8)，儿子的年龄是爸爸的(1/3)．儿子今年几岁？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">72 * (5/8) * (1/3)</gadget>
<output>15</output>

<result>15</result>