Explore the Lesson
Completion requirements
How did it go in the Warm Up above? How did you approach the question? Did you add up \(1 + 2 + 3 + … + 20\)? The answer is \($210\). Is that what you found? Suppose the question had asked how much would you have saved after \(100\) days, would you have even tried to answer the question? In Lesson 1.2, you are going to look at specific sums of numbers called arithmetic series, which are based upon arithmetic sequences. The good news is that you will derive a formula to quickly find these sums!