Hello, aikenfan!
That formula will work, but I prefer the general Sum Formula:Find the sum of the first 100 positive even integers.
Explain how this sum can be found quickly.
Sn = (n/2)(a1 + an)
is that the correct formula?
. .
It is more complicated, but we don't need to calculate the 100th term.
We have: .
Therefore: .
you would use the formula (which is the general formula for the nth term of an arithmetic sequence) where is the nth term, is the first term, is the current number of the term, and is the common difference. you would use the values Soroban gave
thus to find you would compute