bottle of fruit juice weighs exactly 1 kg, and the bottle weighs 250 grams. What is the net weight of this bottle of juice?
一瓶果汁，连瓶称正好1千克，已知瓶重250克，这瓶果汁的净含量是多少克？
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 250</gadget>
<output>750</output>

<result>750</result>