Xiao Hong and Xiao Gang have several stamps. After Xiao Hong gives 10% to Xiao Gang, they both have the same number of stamps. It turns out that Xiao Gang has the same number of stamps as Xiao Hong.
小红和小刚有若干张邮票，小红拿10%给小刚后两人邮票张数一样多，原来小刚的邮票张数是小红的多少．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>