The fruit shop shipped 20 boxes of pears, each weighing 25 kg. Sell 315 kilograms, how many kilograms are left?
水果店运来20箱梨，每箱25千克．卖出315千克，还剩多少千克？
<gadget id="calculator">20 * 25</gadget>
<output>500</output>

<gadget id="calculator">500 - 315</gadget>
<output>185</output>

<result>185</result>