It took 18 minutes to saw a piece of wood into 10 sections, how many minutes would it take to saw it into 20 sections?
把一根木料锯成10段，用了18分钟，如果锯成20段，用多少分钟．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

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