Cut out the largest square from a rectangular cardboard with a length of 7m and a width of 5m. What is the area of the remaining part.
从一个长7m，宽5m的长方形纸板中剪出一个最大的正方形．余下部分的面积为多少．
<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>