The students have to plant 23 apple trees and 56 pear trees in total, 53 have already been planted, how many are still left?
同学们一共要植23棵苹果树和56棵梨树，已经植了53棵，还有多少棵没有植？
<gadget id="calculator">23 + 56</gadget>
<output>79</output>

<gadget id="calculator">79 - 53</gadget>
<output>26</output>

<result>26</result>