bottle of beverage, after drinking half of it at a time, the total weight of the bottle is 700 grams; if (1/3) is drunk, the total weight of the bottle is 800 grams, what is the weight of the bottle in grams?
一瓶饮料，一次喝掉一半以后，连瓶共重700克；如果喝掉(1/3)，连瓶共重800克，则瓶子的重量为多少克．
<gadget id="calculator">800 - 700</gadget>
<output>100</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">100 / (1/6) / 2</gadget>
<output>300</output>

<gadget id="calculator">700 - 300</gadget>
<output>400</output>

<result>400</result>