Subtract a number from the numerator of (1992/1993), add this number to the denominator, the fraction value is (2/3), find this number.
(1992/1993)的分子减去一个数，分母加上这个数后，分数值是(2/3)，求这个数．
<gadget id="calculator">1_992 + 1_993</gadget>
<output>3_985</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">3_985 / 5</gadget>
<output>797</output>

<gadget id="calculator">797 * 2</gadget>
<output>1_594</output>

<gadget id="calculator">1_992 - 1_594</gadget>
<output>398</output>

<result>398</result>