A large grandfather clock strikes its bell once at 1:00, twice at 2:00, three times at 3:00, etcetera. what is the total number of times the bell will be struck in a day? use an arithmetic series to help solve the problem and show how you arrived at your answer.

There is a formula for adding consecutive integers.
sum = (n * (n+1)) / 2
for summing 1 through 12 it is
sum = (12 * 13) / 2 = 156/2 = 78
The clock goes through two "12-hour cycles" in a day, so the answer is 2 * 78 or 156 times.