Huanhuan is 12 years old this year. Grandpa’s age was 9 times that of Huanhuan’s 5 years ago. How old is grandpa this year?
欢欢今年12年，5年前爷爷的年龄是欢欢年龄的9倍，爷爷今年多少岁．
<gadget id="calculator">12 - 5</gadget>
<output>7</output>

<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<gadget id="calculator">63 + 5</gadget>
<output>68</output>

<result>68</result>