If it takes m minutes to saw a piece of wood into two pieces, how many minutes will it take to saw this piece of wood into seven pieces?
把一根木头锯成两段需m分钟，如果将这根木头锯成7段，需要多少分钟．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">1 * 6</gadget>
<output>6</output>

<result>6</result>