The factory originally had 3 tons of aluminum, and the workshop used it twice, 500 kg each time. How many kilograms of aluminum are left in the factory?
工厂原有铝材3吨，车间用了两次，每次用去500千克．问工厂还剩多少千克铝材？
<gadget id="calculator">3 * 1_000</gadget>
<output>3_000</output>

<gadget id="calculator">500 * 2</gadget>
<output>1_000</output>

<gadget id="calculator">3_000 - 1_000</gadget>
<output>2_000</output>

<result>2_000</result>