Grandpa is 65 years old this year, and I am 56 years younger than him. When I was 18, how old was grandpa?
爷爷今年65岁，我比他小56岁，当我18岁的时候，爷爷多少岁．
<gadget id="calculator">65 - 56</gadget>
<output>9</output>

<gadget id="calculator">18 - 9</gadget>
<output>9</output>

<gadget id="calculator">65 + 9</gadget>
<output>74</output>

<result>74</result>