Xiao Ding Ding's grandfather is 72 years old this year, and his age is exactly 8 times that of Xiao Ding Ding. How old is Xiao Ding Ding younger than his grandfather?
小丁丁的爷爷今年已经是72岁了，他的年龄正好是小丁丁的8倍，小丁丁比爷爷小几岁？
<gadget id="calculator">72 / 8</gadget>
<output>9</output>

<gadget id="calculator">72 - 9</gadget>
<output>63</output>

<result>63</result>