Four brothers buy a TV set for their father, the eldest spends (1/2) of the other three, the second spends (1/3) of the other three, and the third spends the other three (1/4), the fourth child spent 520 yuan, how much is this TV set?
兄弟四人为父亲买一台电视机，老大花的费用占其他三人的(1/2)，老二花的费用占其他三人的(1/3)，老三花的费用占其他三人的(1/4)，老四花了520元，这台电视机多少钱？
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/4) - (1/5)</gadget>
<output>13/60 = around 0.216667</output>

<gadget id="calculator">520 / (13/60)</gadget>
<output>2_400</output>

<result>2_400</result>