There are two buckets. The small bucket can hold 4kg of water. The large bucket can hold 11kg of water. No need to weigh. How should these two buckets be used to hold 5kg of water?
有两个水桶．小水桶能盛水4kg．大水桶能盛水11kg．不用秤称．应该怎样使用这两个水桶盛出5kg水来？
<gadget id="calculator">4 - 11</gadget>
<output>-7</output>

<gadget id="calculator">4 + 4 + (-7) + 4</gadget>
<output>5</output>

<result>5</result>