Hope Primary School used to have a rectangular playground, 40 meters long and 30 meters wide. When the campus is expanded, the length of the playground is increased by 10 meters and the width is increased by 5 meters. What is the area of the playground after expansion?
希望小学原来有一个长方形的操场，长40米，宽30米．校园扩建时，操场的长增加10米，宽增加了5米．求扩建后操场的面积是多少公顷？
<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<gadget id="calculator">30 + 5</gadget>
<output>35</output>

<gadget id="calculator">35 / 10_000</gadget>
<output>7/2_000 = around 0.0035</output>

<gadget id="calculator">50 * (7/2_000)</gadget>
<output>7/40 = around 0.175</output>

<result>7/40 = around 0.175</result>