pen is 5.65 yuan, and a notebook is 8.7 yuan. Mr. Chen brought 20 yuan, how much money do you get back?
一支钢笔5.65元，一本笔记本8.7元．陈老师带了20元钱，找回多少钱？
<gadget id="calculator">5.65 + 8.7</gadget>
<output>14.35</output>

<gadget id="calculator">20 - 14.35</gadget>
<output>5.65</output>

<result>5.65</result>