Xiao Wang wants to buy a fountain pen and a ballpoint pen. It is known that the unit price of the fountain pen is 5 yuan, and the unit price of the ballpoint pen is 2.25 yuan cheaper than that of the fountain pen. How much does Xiao Wang need to buy these two school supplies?
小王要买一支钢笔和一支圆珠笔，已知钢笔的单价是5元，圆珠笔的单价比钢笔的便宜2.25元，小王买这两件学习用品一共要用多少钱？
<gadget id="calculator">5 - 2.25</gadget>
<output>2.75</output>

<gadget id="calculator">2.75 + 5</gadget>
<output>7.75</output>

<result>7.75</result>