The ratio of the number of people participating in the sports interest group in the sixth grade to the total number of grades is 1:4. If the 72 people in the chorus are counted, it will account for 1/3 of the total number of people in the whole grade. How many people participate in the sports interest group in the sixth grade ?
六年级参加体育兴趣小组的人数与年级总人数的比是1：4，如果算上合唱的72人，就占全年级总人数的(1/3)，六年级参加体育兴趣小组的有多少人？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">72 / (1/12)</gadget>
<output>864</output>

<gadget id="calculator">864 * (1/4)</gadget>
<output>216</output>

<result>216</result>