It takes 4 minutes to saw a piece of wood into two pieces, how many minutes will it take to saw it into 4 pieces?
把一根木头锯成两段需要4分钟，如果锯成4段，要多少分钟．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

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

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

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<result>12</result>