There are some bricks on the construction site, (1/3) of the total number is used for the first time, and (3/4) of the remaining bricks are used for the second time. If 2400 bricks are used for the second time, how many bricks are there on the construction site?
工地上有一些砖，第一次用去总数的(1/3)，第二次用去余下块数的(3/4)．如果第二次用去2400块，工地上原有砖多少块？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(2/3) * (3/4)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2_400 / (1/2)</gadget>
<output>4_800</output>

<result>4_800</result>