The upper base of a trapezoid is 4 meters, the lower base is 3 meters, and the height is 20 decimeters. What is the area of the trapezoid in square meters?
一个梯形的上底是4米，下底3米，高20分米，这个梯形的面积是多少平方米．
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

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

<gadget id="calculator">7 * 1</gadget>
<output>7</output>

<result>7</result>