Xiaogang buys an exercise book and a pencil in the store. The exercise book is 1.6 yuan each, and the pencil is 0.5 yuan each. If you pay the salesperson 5 yuan, how much should you get back?
小刚在商店里买一个练习本和一支铅笔，练习本1.6元1个，铅笔0.5元一支．付给售货员5元，应找回多少元？
<gadget id="calculator">1.6 + 0.5</gadget>
<output>2.1</output>

<gadget id="calculator">5 - 2.1</gadget>
<output>2.9</output>

<result>2.9</result>