For tree planting on Arbor Day, the school bought 160 camphor trees, 28 fewer than fir trees, and divided these trees on average among 12 classes for planting. How many trees should each class plant?
植树节植树，学校买来樟树160棵，比杉树少28棵，把这些树平均分给12个班级种，每个班级要种多少棵？
<gadget id="calculator">160 + 28 + 160</gadget>
<output>348</output>

<gadget id="calculator">348 / 12</gadget>
<output>29</output>

<result>29</result>