The young pioneers of a certain school wanted to plant a batch of trees, the upper grades planted (1/2) of the total number, and the lower grades planted (1/3) of the total number. If the upper grades plant 150 more saplings than the lower grades, how many saplings are there in total?
某校少先队员要植一批树，高年级植了总数的(1/2)，低年级植了总数的(1/3)．如果高年级比低年级多植150棵，那么这批树苗共有多少棵？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">150 / (1/6)</gadget>
<output>900</output>

<result>900</result>