A ballpoint pen is 6.50 yuan, a mechanical pencil is 2.85 yuan, and my mother bought 10 ballpoint pens. 10 mechanical pencils, give the salesperson 100 yuan, how much should I get back?
一枝圆珠笔6.50元，-枝自动铅笔2.85元，妈妈买了10枝圆珠笔．10枝自动铅笔，给售货员100元，应找回多少钱？
<gadget id="calculator">6.5 * 10</gadget>
<output>65</output>

<gadget id="calculator">2.85 * 10</gadget>
<output>28.5</output>

<gadget id="calculator">65 + 28.5</gadget>
<output>93.5</output>

<gadget id="calculator">100 - 93.5</gadget>
<output>6.5</output>

<result>6.5</result>