Each of the two pieces of wood is 28 meters long. Now they need to be sawed into a 4-meter-long piece of wood, and it takes 2 minutes to saw each section. How many minutes did it take to saw all of them?
两根木材各长28米，现在需要将它们锯成4米长的木材，每锯开一段需要2分钟．全部锯完需要花多少分钟？
<gadget id="calculator">28 / 4</gadget>
<output>7</output>

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

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>