rectangular playground is drawn on a map with a scale of (1/1000), the length is 7 cm, and the width is 5 cm. What is the actual area of the playground in square meters?
一个长方形操场，画在比例尺是(1/1000)的图上，长为7厘米，宽为5厘米，操场实际面积是多少平方米．
<gadget id="calculator">1 / 1_000</gadget>
<output>1/1_000 = around 0.001</output>

<gadget id="calculator">7 / (1/1_000) / 100</gadget>
<output>70</output>

<gadget id="calculator">5 / (1/1_000) / 100</gadget>
<output>50</output>

<gadget id="calculator">70 * 50</gadget>
<output>3_500</output>

<result>3_500</result>