Hope that the primary school brought 25,000 pieces of tiles to pave the ground. After some of them are used, there are still (2/5) left. How many pieces were used?
希望小学运来25000块花砖铺地面，用去一部分后，还剩(2/5)，用了多少块．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">25_000 * (3/5)</gadget>
<output>15_000</output>

<result>15_000</result>