Xiaohua said that this year his age is 6 years younger than his grandfather's (2/7). It is known that Xiaohua is 12 years old this year, how old is grandpa? (Solution of column equation)
小华说，今年他的年龄比爷爷的(2/7)还小6岁．已知小华今年12岁，爷爷今年多少岁？(列方程解)
<gadget id="calculator">6 + 12</gadget>
<output>18</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">18 / (2/7)</gadget>
<output>63</output>

<result>63</result>