A processing fee of 3 yuan is required to saw a steel pipe into 3 sections. According to this calculation, how much processing fee is required to pay for sawing a steel pipe into 7 sections.
把一根钢管锯成3段需付3元加工费，照这样计，把钢管锯成7段需付加工费多少元．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

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

<gadget id="calculator">(3/2) * 6</gadget>
<output>9</output>

<result>9</result>