Congcong is 4 years old this year, and his father is 7 times as old as Congcong. How many times was his father's age last year?
聪聪今年4岁，爸爸的年龄是聪聪的7倍，去年爸爸的年龄是聪聪的几倍？
<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<gadget id="calculator">28 - 1</gadget>
<output>27</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">27 / 3</gadget>
<output>9</output>

<result>9</result>