A rectangle is 8 meters long and 5 meters wide, what is the remaining area in square meters after cutting out the largest square
一个长方形长8米，宽5米，剪去一个最大的正方形后，剩余面积是多少平方米
<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">40 - 25</gadget>
<output>15</output>

<result>15</result>