If a triangle is 30 square centimeters less than the area of a parallelogram with the same base and height, what is the area of the triangle in square centimeters?
一个三角形比与它等底等高的平行四边形的面积少30平方厘米，则这个三角形的面积是多少平方厘米．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">30 / 1</gadget>
<output>30</output>

<result>30</result>