The upper base of a trapezoid is 24 cm, the lower base is 3 decimeters, and the height is 1 decimeter. What is the area in square decimeters?
一个梯形的上底是24厘米，下底是3分米，高是1分米，面积是多少平方分米．
<gadget id="calculator">24 / 10</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">(12/5) + 3</gadget>
<output>27/5 = around 5.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(27/5) * (1/2)</gadget>
<output>27/10 = around 2.7</output>

<result>27/10 = around 2.7</result>