A triangular iron sheet has a base of 5 decimeters and a height of 40 cm. What is the area of this iron sheet in square decimeters?
一块三角形铁皮，底是5分米，高是40厘米，这块铁皮的面积是多少平方分米．
<gadget id="calculator">40 / 10 / 2</gadget>
<output>2</output>

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

<result>10</result>