Find the sum of odd integers from 1 to 1001.

To find the sum of odd integers from 1 to 1001, we can use the formula for the sum of an arithmetic series:

Sum = n/2 * (first term + last term)

In this case, the first term is 1, the last term is 1001, and the common difference is 2 (since we are summing odd integers).

n = (last term - first term) / common difference + 1
n = (1001 - 1) / 2 + 1
n = 500

Sum = 500/2 * (1 + 1001)
Sum = 250 * 1002
Sum = 250,500

Therefore, the sum of odd integers from 1 to 1001 is 250,500.