There are 18 coins with 2 jiao and 5 jiao, totaling 6 yuan. How many 2 dime coins are there?
有2角和5角的硬币共18枚，一共6元钱．2角硬币有多少枚．
<gadget id="calculator">5 * 18</gadget>
<output>90</output>

<gadget id="calculator">6 * 10</gadget>
<output>60</output>

<gadget id="calculator">90 - 60</gadget>
<output>30</output>

<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<result>10</result>