It takes 8 minutes for Uncle Wang to walk from the first telegraph pole to the fifth; if he walks from the first telegraph pole to the 20th, how long should it take?
王大爷从第1根电线杆走到第5根，用8分钟；如果从第1根电线杆走到第20根，应该用多少时间？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">2 * 19</gadget>
<output>38</output>

<result>38</result>