Fill an empty jug with beverages, pour 3 cups of beverages, the total weight of the jug is 860 grams, and pour 5 cups of beverages, the total weight of the jug is 1320 grams. How many grams does an empty jug weigh?
往一只空水壶里灌饮料，灌进3杯饮料，连壶共重860克，灌进5杯饮料，连壶共重1320克．空水壶重多少克？
<gadget id="calculator">1_320 - 860</gadget>
<output>460</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">460 / 2</gadget>
<output>230</output>

<gadget id="calculator">230 * 3</gadget>
<output>690</output>

<gadget id="calculator">860 - 690</gadget>
<output>170</output>

<result>170</result>