Three consecutive natural numbers, the middle number is the sum of the three numbers ((())/(())); in a subtraction formula, the subtrahend is equivalent to (3/5) of the minuend, and the difference is the subtrahend ( (())/(())); (4/9) of the number A is (1/4), what is the number A.
三个连续自然数，中间数是三数和的((())/(()))；在一道减法算式中，减数相当于被减数的(3/5)，差是减数的((())/(()))；甲数的(4/9)是(1/4)，甲数是多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(1/4) / (4/9)</gadget>
<output>9/16 = around 0.5625</output>

<result>9/16 = around 0.5625</result>