Run 5 laps along a swimming pool with a difference of 30 meters in length and width to prepare for entering the water. It is known that you have run a total of 900 meters. How many square meters does this swimming pool occupy?
沿长、宽相差30米的游泳池跑5圈做下水前的准备活动，已知共跑了900米，这个游泳池占地多少平方米．
<gadget id="calculator">900 / 5 / 2</gadget>
<output>90</output>

<gadget id="calculator">90 - 30</gadget>
<output>60</output>

<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">30 + 30</gadget>
<output>60</output>

<gadget id="calculator">60 * 30</gadget>
<output>1_800</output>

<result>1_800</result>