This year, grandpa's age is 6 times that of Xiaopang's. The combined age of the two is 84 years old. How old is grandpa this year?
今年爷爷的年龄是小胖的6倍，两人年龄的和是84岁，爷爷今年几岁？
<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">84 / 7</gadget>
<output>12</output>

<gadget id="calculator">84 - 12</gadget>
<output>72</output>

<result>72</result>