If 2△3=2+3+4=9, 5△4=5+6+7+8=26, according to this calculation, then 9△5=how much.
如果2△3=2+3+4=9，5△4=5+6+7+8=26，照这样计算，则9△5=多少．
<gadget id="calculator">9 + 10 + 11 + 12 + 13</gadget>
<output>55</output>

<result>55</result>