Three classes of the fifth grade in a certain school carried out tree planting work, among which 230 trees were not planted by the fifth and second classes, and 250 were not planted by the fifth and first classes. Now we know that the five. • How many trees did the third shift plant?
某学校五年级三个班开展植树劳动，其中230棵不是五•二班栽的，有250棵不是五•一班栽的，现在知道五•一、五•二班共栽180棵，那么五•三班栽了多少棵？
<gadget id="calculator">250 + 230 + 180</gadget>
<output>660</output>

<gadget id="calculator">660 / 2</gadget>
<output>330</output>

<gadget id="calculator">330 - 180</gadget>
<output>150</output>

<result>150</result>