Cut out the largest square from a cardboard with a length of 25 cm and a width of 20 cm. What is the area of the remaining part?
从一个长25cm，宽20cm的纸板上剪下一个最大的正方形，剩余部分的面积是多少？
<gadget id="calculator">25 - 20</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>