The price of a fountain pen is 12.8 yuan, which is 6.5 yuan more expensive than a ballpoint pen. How much is the price of a ballpoint pen? (solution by equation)
一枝钢笔的价钱是12.8元，比一枝圆珠笔贵6.5元．一枝圆珠笔的价钱是多少元？(用方程解)
<gadget id="calculator">12.8 - 6.5</gadget>
<output>6.3</output>

<result>6.3</result>