A pile of sand weighs 800 kilograms, 325 kilograms are transported away for the first time, and 168 kilograms are transported away for the second time, how many kilograms are left?
一堆沙子重800千克，第一次运走325千克，第二次运走168千克，还剩下多少千克？
<gadget id="calculator">325 + 168</gadget>
<output>493</output>

<gadget id="calculator">800 - 493</gadget>
<output>307</output>

<result>307</result>