It takes (1/20) hour to saw a piece of wood into 3 pieces. If it takes the same time to saw each time, how many hours will it take to saw 7 segments?
一根木料锯成3段，需要(1/20)小时．如果每锯一次所用时间相同，那么锯成7段，需要多少小时．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">(1/20) / 2</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">6 * (1/40)</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>