I finally earned 10 yuan more after 10 yuan invested. The story starts from 4 yuan winning by 5 pieces of lotteries worthed 10 yuan I got which I changed to another 2 pieces of lo...

• 我先买了10块钱的卡(5张)；中了4块钱;接著我用这4块钱换了2张；又中了4块.我于是再用这4块钱换了两张；就中了8块；接著我换了4张；中了4块；最后我用这4块又买了两张；中了20块....于是最终我赚了10块.