It costs 4.5 yuan more to buy 3 pens than to buy 5 ballpoint pens. The price of each ballpoint pen is 0.9 yuan, how much is each pen?
买3支钢笔要比买5支圆珠笔多花4.5元．每支圆珠笔的价钱是0.9元，每支钢笔多少元？
<gadget id="calculator">0.9 * 5</gadget>
<output>4.5</output>

<gadget id="calculator">4.5 + 4.5</gadget>
<output>9</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<result>3</result>