The number A is the sum of the numbers B, C, and D (1/2), the number B is the sum of the numbers A, C, and D (1/3), and the number C is the number A, B, and D The sum of the numbers (1/3), the known number D is 260, find the sum of the numbers A, B, C and D.
甲数是乙数、丙数、丁数之和的(1/2)，乙数是甲数、丙数、丁数之和的(1/3)，丙数是甲数、乙数、丁数之和的(1/3)，已知丁数是260，求甲数、乙数、丙数、丁数的和．
<gadget id="calculator">6 * 260</gadget>
<output>1_560</output>

<result>1_560</result>