Uncle Zhang rented 6 cars and transported 140 boxes of fruit, each large truck transported 25 boxes of fruit, and each small car transported 20 boxes of fruit, so how many small cars did he rent?
张大爷租了6辆车，运进水果140箱，每辆大货车运25箱水果，每辆小车运20箱水果，那么他租了多少辆小车．
<gadget id="calculator">6 * 20</gadget>
<output>120</output>

<gadget id="calculator">140 - 120</gadget>
<output>20</output>

<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">20 / 5</gadget>
<output>4</output>

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

<result>2</result>