What is the sum of integers from 1 to 20?
What is the sum of integers from 1 to 20?
Approach: Use formula n(n+1)/2.
210. 20 * 21 / 2 = 10 * 21 = 210.
Follow-up: What is the sum of 1 to 50?
Key concepts: arithmetic series, summation.
What is the sum of integers from 1 to 20?
Approach: Use formula n(n+1)/2.
210. 20 * 21 / 2 = 10 * 21 = 210.
Follow-up: What is the sum of 1 to 50?
Key concepts: arithmetic series, summation.