There are two buckets with a total of 40 catties of water. Now pour 7 catties from the No. 1 bucket into the No. 2 bucket, and the water in the two buckets is the same. How much water is in the No. 1 bucket? catty.
有两个桶子里面共有水40斤，现在从一号桶子里往二号桶子里面倒7斤，则两个桶子里的水一样多了，那么原来一号桶子里有水多少斤．
<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">40 + 14</gadget>
<output>54</output>

<gadget id="calculator">54 / 2</gadget>
<output>27</output>

<result>27</result>