To calculate the sum \( F \) given in the image, we need to evaluate each fraction and then sum them up. The expression is:

\[ F = \frac{1}{2023 \times 2022} + \frac{1}{2022 \times 2021} + \frac{1}{2021 \times 2020} + \frac{1}{3.2 \times 2.1} \]

Let's calculate each term separately:

1. \(\frac{1}{2023 \times 2022}\):
\[ 2023 \times 2022 = 4098506 \]
\[ \frac{1}{4098506} \approx 2.44 \times 10^{-7} \]

2. \(\frac{1}{2022 \times 2021}\):
\[ 2022 \times 2021 = 4084442 \]
\[ \frac{1}{4084442} \approx 2.45 \times 10^{-7} \]

3. \(\frac{1}{2021 \times 2020}\):
\[ 2021 \times 2020 = 4070420 \]
\[ \frac{1}{4070420} \approx 2.46 \times 10^{-7} \]

4. \(\frac{1}{3.2 \times 2.1}\):
\[ 3.2 \times 2.1 = 6.72 \]
\[ \frac{1}{6.72} \approx 0.149 \]

Now, sum these values:
\[ F \approx 2.44 \times 10^{-7} + 2.45 \times 10^{-7} + 2.46 \times 10^{-7} + 0.149 \]

Since the first three terms are very small compared to the fourth term, the sum is dominated by the fourth term:
\[ F \approx 0.149 \]

Thus, the sum \( F \) is approximately \( 0.149 \).