A person bought a chicken for 8 yuan, sold it for 9 yuan, then he thought it was not worth it, bought it back for 10 yuan, and sold it to another person for 11 yuan. How much did he earn?
一个人花8块钱买了一只鸡，9块钱卖掉了，然后他觉得不划算，花10块钱又买回来了，11块卖给另外一个人．问他赚了多少？
<gadget id="calculator">9 - 10</gadget>
<output>-1</output>

<gadget id="calculator">(-8) + (-1) + 11</gadget>
<output>2</output>

<result>2</result>