If the length of a rectangle is increased by 2 cm and the width by 5 cm, a square with an area of 100 cm2 is obtained. What is the area of the original rectangle?
一个长方形，如果长增加2厘米，宽增加5厘米，就得到一个面积为100平方厘米的正方形，那么原长方形的面积是多少．
<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

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

<result>40</result>