The number of people who participated in the mathematics competition in the fifth grade accounted for (1/3) of the total number of students in the school, and the number of people who participated in the fourth grade was less than that of the fifth grade (1/4).
五年级参加数学竞赛的人数占全校总人数的(1/3)，四年级参加的人数比五年级少(1/4)，两个年级参加的人数占全校参加人数的几分之几？
<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 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(1/3) * (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) + (1/4)</gadget>
<output>7/12 = around 0.583333</output>

<result>7/12 = around 0.583333</result>