The teachers and students of Dongfeng Elementary School donated 3,450 yuan to the disabled, of which the teacher donated 1,050 yuan. The ratio of donations for the junior, middle and senior grades is 3:4:5. How much is the donation for the senior grades?
东风小学师生为残疾人捐款3450元，其中老师捐款1050元，低、中、高年级捐款的钱数比是3：4：5，高年级捐款多少元？
<gadget id="calculator">3_450 - 1_050</gadget>
<output>2_400</output>

<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">2_400 * (5/12)</gadget>
<output>1_000</output>

<result>1_000</result>