2 coats and 3 pairs of trousers total 480 yuan, 4 coats and 2 pairs of trousers total 640 yuan, how much is a coat more expensive than a pair of trousers?
2件上衣和3条裤子共480元，4件上衣和2条裤子共640元，一件上衣比一条裤子贵多少元．
<gadget id="calculator">480 * 2</gadget>
<output>960</output>

<gadget id="calculator">960 - 640</gadget>
<output>320</output>

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

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<gadget id="calculator">80 * 3</gadget>
<output>240</output>

<gadget id="calculator">480 - 240</gadget>
<output>240</output>

<gadget id="calculator">240 / 2</gadget>
<output>120</output>

<gadget id="calculator">120 - 80</gadget>
<output>40</output>

<result>40</result>