Fill the bottle with water, even the bottle weighs 1.2 kg, pour out half of the water in the bottle, and add the bottle to weigh 750 grams. How many kilograms does the bottle weigh?
瓶里装满水，连瓶称1.2千克，把瓶里的水倒去一半，再连瓶称是750克．瓶重多少千克？
<gadget id="calculator">750 / 1_000</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1.2 - (3/4)</gadget>
<output>0.45</output>

<gadget id="calculator">0.45 * 2</gadget>
<output>0.9</output>

<gadget id="calculator">1.2 - 0.9</gadget>
<output>0.3</output>

<result>0.3</result>