The school has a rectangular experimental field. If the width of the test field is increased by 5 meters or the length is increased by 8 meters, the area will be increased by 40 square meters compared with the original one. Do you know the area of the original test field in square meters?
学校有一块长方形试验田．如果这块试验田的宽增加5米或长增加8米，面积都比原来增加40平方米．你知道原来试验田的面积是多少平方米吗？
<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<result>40</result>