When a=2, b=5, then how much is 8a-2b=.
当a=2，b=5时，那么8a-2b=多少．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">16 - 10</gadget>
<output>6</output>

<result>6</result>