Use an empty cup to pour pure water into the jug. When 2 cups are poured in, the weight of the jug is 800 grams. If 5 cups are poured, the weight of the jug is 1250 grams. When 8 cups are poured, the weight of the jug is 800 grams.
用一个空杯子往壶中倒纯净水，当倒进2杯时，连壶重800克，如果倒进5杯，连壶重1250克，问倒进8杯时连壶重多少克．
<gadget id="calculator">1_250 - 800</gadget>
<output>450</output>

<gadget id="calculator">1_250 + 450</gadget>
<output>1_700</output>

<result>1_700</result>