The current price of a TV set is 2400 yuan (1/7) lower than the original price. How much is this TV set lower than the original price?
一台电视机，现价2400元比原价降低(1/7)，这台电视机比原价降低了多少元？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">2_400 / (6/7)</gadget>
<output>2_800</output>

<gadget id="calculator">2_800 - 2_400</gadget>
<output>400</output>

<result>400</result>