If it takes 3 minutes to saw a steel bar into two pieces, how many minutes will it take to saw it into 10 pieces?
把一根钢条锯成两段要用3分钟，如果锯成10段需要多少分钟．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

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

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

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

<result>27</result>