The base of the triangle is 18 meters, the height is 15 meters, what is the area?
三角形的底是18米，高是15米，面积是多少．
<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">18 * (15/2)</gadget>
<output>135</output>

<result>135</result>