Xiao Ming bought 24 stamps of 2 yuan and 8 cents in total, and spent 30 yuan, so how many stamps of 8 cents are there?
小明买了2元和8角的两种邮票共24枚，用去30元，则8角的邮票有多少枚．
<gadget id="calculator">2 * 24</gadget>
<output>48</output>

<gadget id="calculator">48 - 30</gadget>
<output>18</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<gadget id="calculator">10 / 12</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">18 * (5/6)</gadget>
<output>15</output>

<result>15</result>