barrel of gasoline weighs 850 grams when (1/2) is used up, and 1000 grams when (1/3) is used up. What is the weight in grams?
一桶汽油，当用去(1/2)后连桶共重850克，当用去(1/3)后连桶共重1000克，求同的重量是多少克？
<gadget id="calculator">1_000 - 850</gadget>
<output>150</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">150 / (1/6)</gadget>
<output>900</output>

<gadget id="calculator">900 * (1/2)</gadget>
<output>450</output>

<gadget id="calculator">850 - 450</gadget>
<output>400</output>

<result>400</result>