Zhang Jun and Huang Xin went to buy the same ballpoint pen and watercolor pen, Zhang Jun bought a watercolor pen and a ballpoint pen for 6.8 yuan, Huang Xin bought a watercolor pen and two ballpoint pens for 9.4 yuan, you know one How much is the ballpoint pen?
张军和黄鑫去买同样的圆珠笔和水彩笔，张军买了一支水彩笔和一支圆珠笔用了6.8元，黄鑫买了一支水彩笔和两支圆珠笔用了9.4元，你知道一支圆珠笔多少元吗？
<gadget id="calculator">9.4 - 6.8</gadget>
<output>2.6</output>

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

<gadget id="calculator">2.6 / 1</gadget>
<output>2.6</output>

<result>2.6</result>