wooden board with a length of 10 decimeters and a width of 4 decimeters is sawn into two small rectangular wooden boards on average. What is the area of each small rectangular wooden board in square decimeters?
一块长10分米、宽4分米的木板，平均锯成两块小长方形的木板，每块小长方形木板的面积是多少平方分米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<result>20</result>