# Calculation is beautiful

Algebra Level 3

$$a_1,a_2,a_3,\ldots, a_{98}$$ are terms in an arithmetic progression with common difference 1 such that their sum is 137.

What is the sum of the even terms of this progression? That is, what is the value of $$a_2+a_4+a_6+\cdots+a_{98}$$?

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