To find the sum of an arithmetic series, we can use the formula:

Sn = (n/2)(a + L)

where Sn is the sum of the series, n is the number of terms, a is the first term, and L is the last term.

In this case, the first term (a) is 1, and the last term (L) is 2023. We need to find the number of terms (n).

The formula to find the number of terms in an arithmetic series is:

n = (L - a)/d + 1

where d is the common difference. In this case, the common difference is 2, since we are adding odd numbers.

n = (2023 - 1)/2 + 1
n = 2022/2 + 1
n = 1011 + 1
n = 1012

Now that we have the number of terms, we can find the sum (Sn):

Sn = (n/2)(a + L)
Sn = (1012/2)(1 + 2023)
Sn = 506(2024)
Sn = 1,024,144

Therefore, the sum of the series 1 + 3 + 5 + ... + 2023 is 1,024,144.