If the two sides of a right triangle are 4 cm, what is its area?
直角三角形的两条直角边都是4厘米，它的面积应该是多少．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>