Algebra & Equations
Sum of First n Integers
1 + 2 + … + n.
Formula
Formula
Σ = n(n+1)2
Variables
| Symbol | Definition | Type & range | Units | Role |
|---|---|---|---|---|
| n | upper bound | integer (ℤ) | — | input |
Try it yourself
Interactive calculator
Worked examples
Example 1
Givenn = 100
Result5050
Example 2
Givenn = 10
Result55