It takes 40 minutes to saw a piece of staff with uniform thickness into 9 small pieces; if it is cut into 0.7-meter-long pieces, it takes 30 minutes. How many meters is this wood?
把一根粗细均匀的幕僚，锯成9小段，用40分钟；如果锯成都是0.7米长的小段，要30分钟，这根木料长多少米．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">30 / 5</gadget>
<output>6</output>

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

<gadget id="calculator">7 * 0.7</gadget>
<output>4.9</output>

<result>4.9</result>