A piece of cake, eat it (1/4) with a smile, and then eat the rest (1/3), how much of this cake is left at this time.
一块蛋糕，笑笑吃去它的(1/4)，接着淘淘吃去剩下的(1/3)，这时还剩下这个蛋糕的多少．
<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</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(3/4) * (2/3)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>