There are a total of 7 tons of sand on the construction site, and a large truck transported 3,000 kilograms. How many kilograms are left?
工地上一共有7吨沙子，一辆大卡车运走了3000千克，还剩多少千克？
<gadget id="calculator">7 * 1_000</gadget>
<output>7_000</output>

<gadget id="calculator">7_000 - 3_000</gadget>
<output>4_000</output>

<result>4_000</result>