Your method is completely correct. The first term will be 6 and each subsequent term can be obtained by adding 6 to the previous one, meaning the common difference is 6. The number of terms is given by the highest number that is divisible by 6 and dividing it by 6; that is 996/6 = 166 Then we simply apply the formula for arithmetic sequence sum: S = n/2 [2a₁ + (n - 1)d] S = 166/2 [ 2(6) + (166 - 1)6] S = 83,166
