Buying 3 pencils and 2 ballpoint pens costs 2 yuan and 7 jiao, and buying 2 pencils and 3 ballpoint pens costs 3 yuan and 3 jiao. How many corners is a pencil.
买3枝铅笔和2枝圆珠笔共要2元7角，买2枝铅笔和3枝圆珠笔共要3元3角．一枝铅笔多少角．
<gadget id="calculator">27 * 3</gadget>
<output>81</output>

<gadget id="calculator">33 * 2</gadget>
<output>66</output>

<gadget id="calculator">81 - 66</gadget>
<output>15</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<result>3</result>