There are 400 pear trees in the farmer's orchard, which is twice the number of apple trees. How many apple trees are there?
农夫果园里有梨树400棵，是苹果树棵数的两倍，苹果树有多少．
<gadget id="calculator">400 / 2</gadget>
<output>200</output>

<result>200</result>