100 teachers and students planted a total of 100 trees, each teacher planted 3 trees, and every 2 students planted 1 tree. How many trees did the students plant?
100名师生共栽100棵树，老师每人栽3棵，学生每2人栽1棵．求学生栽了多少棵树？
<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">100 - 50</gadget>
<output>50</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 - (1/2)</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">50 / (5/2)</gadget>
<output>20</output>

<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<result>40</result>