The three children ate a piece of cake together, Xiaohong ate (1/2) piece, Xiaojun ate (1/4) piece, and the rest Xiaogang ate, so how much did Xiaogang eat?
三个小朋友合吃一块蛋糕，小红吃了(1/2)块，小军吃了(1/4)块，剩下的小刚吃了，那么小刚吃了多少？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 - (1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>