It takes the same time to saw a section of wood each time. It takes 12 minutes to saw 3 sections, and how many minutes to saw 4 sections. Tips: how many times do you need to saw the 3 sections? What about sawing 4 sections?
锯一段木料，每次用时相同，锯3段用12分，锯4段用多少分．提示：锯3段要锯几次？锯4段呢？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

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

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>