A fruit juice with a net content of 1 liter, how many milliliters are drunk, and there are 450 milliliters left.
一种净含量是1升的果汁，喝去多少毫升，还剩450毫升．
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 450</gadget>
<output>550</output>

<result>550</result>