Answer :

To solve the expression [tex]\((2019 - (2000 - (10 - 9))) - (2000 - (10 - (9 - 2019)))\)[/tex], let's break it down step-by-step:

1. Evaluate the innermost parentheses:
[tex]\[ (10 - 9) = 1 \][/tex]
[tex]\[ (9 - 2019) = -2010 \][/tex]

2. Substitute these values back into the expression:
[tex]\[ (2019 - (2000 - 1)) - (2000 - (10 - (-2010))) \][/tex]

3. Simplify the expressions inside the outer parentheses:
[tex]\[ 2000 - 1 = 1999 \][/tex]
[tex]\[ 10 - (-2010) = 10 + 2010 = 2020 \][/tex]

4. Substitute these values back into the expression:
[tex]\[ (2019 - 1999) - (2000 - 2020) \][/tex]

5. Simplify the remaining expressions:
[tex]\[ 2019 - 1999 = 20 \][/tex]
[tex]\[ 2000 - 2020 = -20 \][/tex]

6. Substitute these final values and complete the calculation:
[tex]\[ 20 - (-20) = 20 + 20 = 40 \][/tex]

Therefore, the value of the expression [tex]\((2019 - (2000 - (10 - 9))) - (2000 - (10 - (9 - 2019)))\)[/tex] is [tex]\(\boxed{40}\)[/tex].