Use a cup to pour water into the empty bottle. If 4 cups of water are poured into it, the weight of the whole bottle is 560 grams. If 6 cups of water are poured into it, the weight of the whole bottle is 650 grams. How many grams does this empty bottle weigh?
用一个杯子向空瓶中倒水，如果倒进4杯水，那么连瓶共重560克，如果倒进6杯水，那么连瓶重650克．这个空瓶重多少克？
<gadget id="calculator">650 - 560</gadget>
<output>90</output>

<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<gadget id="calculator">45 * 4</gadget>
<output>180</output>

<gadget id="calculator">560 - 180</gadget>
<output>380</output>

<result>380</result>