When a=2, b=5, then how much is 8a-3b=.
当a=2，b=5时，那么8a-3b=多少．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

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

<gadget id="calculator">16 - 15</gadget>
<output>1</output>

<result>1</result>