If it takes 4 minutes to saw a piece of wood into 3 pieces, how many minutes will it take to saw it into 5 pieces?
一根木头，把它锯成3段需要4分钟，如果把它锯成5段需要多少分钟．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

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

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<result>8</result>