The grain factory has 2 tons of rice, and after selling some, there are 400 kilograms left. How many kilograms were sold?
粮食厂有2吨大米，卖了一些后还剩400千克，卖了多少千克？
<gadget id="calculator">2 * 1_000</gadget>
<output>2_000</output>

<gadget id="calculator">2_000 - 400</gadget>
<output>1_600</output>

<result>1_600</result>