The distance between every two bus stops is about 1 kilometer. The fare is 1 yuan within 10 kilometers, and 0.5 yuan is added for every additional 1 kilometer. Mr. Li takes the bus from the first stop to the 13th stop, how much is the bus fare.
公共汽车每两站间相距约1公里，10公里以内票价1元，每增加1公里增加0.5元，李老师从第1站坐到第13站下车，车票多少元．
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<result>2</result>