There were originally 25 rows of pear trees planted in the orchard, and each row had the same tree. Later, the same 4 lines were added, so that 72 more trees were added than before. How many pear trees were there in the orchard?
果园里原来栽了25行梨树，每行棵树相同．后来又增加了同样的4行，这样就比原来增加了72棵．果园里原来有多少棵梨树？
<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<gadget id="calculator">18 * 25</gadget>
<output>450</output>

<result>450</result>