In a charity donation activity, the fourth grade of Hope Primary School donated a total of 260 yuan, the donation of the fifth grade was twice that of the fourth grade, and the donation of the sixth grade was 115 yuan less than the total of the fourth and fifth grades. How much is the donation of the sixth grade ?
在一次爱心捐款活动中，希望小学的四年级共捐款260元，五年级捐的款是四年级的2倍，六年级捐的款比四、五年级的总数少115元，六年级捐款多少元？
<gadget id="calculator">260 * 2</gadget>
<output>520</output>

<gadget id="calculator">260 - 115</gadget>
<output>145</output>

<gadget id="calculator">520 + 145</gadget>
<output>665</output>

<result>665</result>