One-third of a class of 39 students took part in a math competition. How many students did not participate in the competition?
Since one-third of the class participated, there are 39 * 1/3 = 
<gadget id="calculator">39*1/3</gadget>
<output>13</output>
13 students who participated in the competition.
This means that 39 - 13 = 
<gadget id="calculator">39-13</gadget>
<output>26</output>
26 students did not participate.

<result>26</result>