The arithmetic series is .

Where is first term of the sequence and d is common difference.

Here ,

Common difference ,

So

The nth term of an arithmetic sequence is .

        (Substitute )

Distribute terms using distributive property: .

                     (Add: 101 + 11 = 112)

Apply subtraction property of equality: a = b then .

(Subtract 112 from each side)

                        (Subtract: )

Apply division property of equality: a = b then .

                   (Divide each side by negative 11)

                              (Cancel common terms)

                                      (Divide: )

Apply sum of an arithmetic series formula: .

                (Substitute )

                      (Add: 101 + 2 = 103)

                                 (Multiply: )

The sum of the arithmetic series is 515.