The smiling grandpa and grandma each ate a piece of watermelon (1/5), what fraction is left?
笑笑的爷爷、奶奶各吃了一个西瓜的(1/5)，还剩几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5) - (1/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>