The price of a bottle of ink is 3.5 yuan. It is 1.6 yuan cheaper than buying a pen. How much does it cost to buy a pen?
一瓶墨水的价格是3.5元．比买一支钢笔便宜1.6元．买一支钢笔需要多少钱？
<gadget id="calculator">3.5 + 1.6</gadget>
<output>5.1</output>

<result>5.1</result>