After Dodney blows out the candles and cuts the cake, he cuts (1/4) for his parents, and cuts 70% of the whole cake for his good friends, and keeps the rest for himself. Dodney eats the cake How much?
逗逗尼吹完蜡烛切蛋糕，他切了(1/4)给爸爸妈妈，又切了整块蛋糕的70%分给了好朋友，剩下的留给自己，逗逗尼吃了蛋糕的几分之几呢？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (1/4) - (7/10)</gadget>
<output>1/20 = around 0.05</output>

<result>1/20 = around 0.05</result>