rectangular swimming pool is 50 meters long, 25 meters wide and 2 meters deep. If you want to paint a layer of cement on the four walls and the bottom of this pool, how many tons of cement will you need if you use 2 kilograms of cement to paint 1 square meter?
一个长方形的游泳池，长50米，宽25米，深2米．如果要给这个水池的四壁和底面粉刷上一层水泥，按粉刷1平方米需用水泥2千克计算，共需水泥多少吨？
<gadget id="calculator">50 * 25</gadget>
<output>1_250</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<gadget id="calculator">100 + 50</gadget>
<output>150</output>

<gadget id="calculator">150 * 2</gadget>
<output>300</output>

<gadget id="calculator">1_250 + 300</gadget>
<output>1_550</output>

<gadget id="calculator">2 / 1_000</gadget>
<output>1/500 = around 0.002</output>

<gadget id="calculator">1_550 * (1/500)</gadget>
<output>31/10 = around 3.1</output>

<result>31/10 = around 3.1</result>