Question

What is the sum of the first 2018 positive integers?

Answer 1

Positive integers normally form an arithmetic sequence such that in this case the initial term is 1 and the common difference is 1.
The number of terms is 2018 and therefore n = 2018
 Sn= n/2( 2a+ (n-1)d)  where Sn is the sum of n terms, a is the first term and d is the common difference.
Substituting the unknowns with the values 
we get Sn = 2018/2 (2 + (2017) 1)
                 = 2018/ 2 (2019)
                 = 4074342/2
                 = 2037171
Therefore the sum of the first 2018 positive integer is 2037171.