There are 10 bicycles and tricycles with a total of 26 wheels. How many bicycles are there?
自行车和三轮车共10辆，总共有26个轮子．自行车有多少辆．
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">26 - 20</gadget>
<output>6</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">6 / 1</gadget>
<output>6</output>

<gadget id="calculator">10 - 6</gadget>
<output>4</output>

<result>4</result>