There are 180 pear trees in Baishan Orchard, accounting for 4/5 of the total number of fruit trees, and 1 apple tree accounting for 20% of the total number of fruit trees. How many apple trees are there?
白山果园有梨树180棵，占果树总棵数的(4/5)，苹果树的棵树占果树总棵数的20%，苹果树有多少棵？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">180 / (4/5)</gadget>
<output>225</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">225 * (1/5)</gadget>
<output>45</output>

<result>45</result>