Calculation: ((1999+1998*2000)/(1999*2000-1)).
计算：((1999+1998*2000)/(1999*2000-1))．
<gadget id="calculator">1_998 * 2_000</gadget>
<output>3_996_000</output>

<gadget id="calculator">1_999 + 3_996_000</gadget>
<output>3_997_999</output>

<gadget id="calculator">1_999 * 2_000</gadget>
<output>3_998_000</output>

<gadget id="calculator">3_998_000 - 1</gadget>
<output>3_997_999</output>

<gadget id="calculator">3_997_999 / 3_997_999</gadget>
<output>1</output>

<result>1</result>