Beibei is 9 years old this year. Add 5 to grandpa's age, multiply by 3, then divide by 10, and then subtract 12, which happens to be Beibei's age. May I ask how old is grandpa?
贝贝今年9岁，爷爷的年龄加上5，再乘以3，然后除以10，再减去12，正好是贝贝的岁数．请问爷爷今年多少岁？
<gadget id="calculator">9 + 12</gadget>
<output>21</output>

<gadget id="calculator">10 / 3</gadget>
<output>10/3 = around 3.333333</output>

<gadget id="calculator">21 * (10/3)</gadget>
<output>70</output>

<gadget id="calculator">70 - 5</gadget>
<output>65</output>

<result>65</result>