So many questions ~ I'm afraid no one wants to answer them one by one ~ The picture is too small to see clearly ~ Let me tell you something:

First question

The molecule 2004 * 2004-2004+1= 2004 * 2004-2003 is stationary.

Denominators 2004 * 2004-2004 * 2003+2003 * 2003 = 2004 * 2004+2003 * (2003-2004) = 2004 * 2004-2003.

So far ~ numerator equals denominator ~ original formula equals one

I can't see the second question clearly.

Third question

9999=3333*3 Similarly, 6666=3333*2.

Parentheses can be rewritten as 3333 * (1/2+1/2+9) * 9/7-1330 = 2003.

No ~ the words are too small ~ the eyes are blurred ~ I can't help you.