If the length of a rectangle increases by 2 centimeters, the area increases by 10 square centimeters, and if the width decreases by 3 centimeters, the area decreases by 18 square centimeters. Find the area of the original rectangle.
一个长方形若长增加2厘米，面积就增加10平方厘米，若宽减少3厘米，面积就减少18平方厘米．求原来长方形的面积．
<gadget id="calculator">18 / 3</gadget>
<output>6</output>

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

<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<result>30</result>