Xiao Ming said that this year his age is 3 years younger than his grandfather's (1/3). It is known that Xiao Ming is 15 years old this year, how old is grandpa? (Solution of column equation)
小明说，今年他的年龄比爷爷的(1/3)还小3岁．已知小明今年15岁，爷爷今年多少岁？(列方程解)
<gadget id="calculator">3 + 15</gadget>
<output>18</output>

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

<gadget id="calculator">18 / (1/3)</gadget>
<output>54</output>

<result>54</result>