After drinking half of a cup of drink, pour another 200ml into the cup, and the drink at this time is exactly the original (3/4). How many milliliters is this cup of drink?
一杯饮料喝去一半后，又倒入杯中200毫升，这时的饮料正好是原来的(3/4)．原来这杯饮料有多少毫升？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

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

<gadget id="calculator">(3/4) - (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">200 / (1/4)</gadget>
<output>800</output>

<result>800</result>