It is stipulated that "△" is a new operation, a△b means 2a-b, if 4△3=2*4-3=5, then 10△(9△6)=what.
规定"△"是一种新运算，a△b表示2a-b，如果4△3=2*4-3=5，那么10△(9△6)=多少．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">2 * 9</gadget>
<output>18</output>

<gadget id="calculator">18 - 6</gadget>
<output>12</output>

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

<result>8</result>