Dad is 40 years old this year. Xiaofang's age is (3/10) of his father's age, and it happens to be (1/6) of his grandfather's age. How old is grandpa this year? (column equation solution)
爸爸今年40岁，小芳的年龄是爸爸年龄的(3/10)，又恰好是爷爷年龄的(1/6)，爷爷今年多少岁？(列方程解答)
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">40 * (3/10)</gadget>
<output>12</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">12 / (1/6)</gadget>
<output>72</output>

<result>72</result>