A notebook is 18.9 yuan, and Mingming pays the salesperson 20 yuan, how much should the salesperson give Mingming?
一个笔记本18.9元，明明付给售货员20元，售货员应找给明明多少钱？
<gadget id="calculator">20 - 18.9</gadget>
<output>1.1</output>

<result>1.1</result>