Addition is the most basic arithmetic operation, but adding long lists of decimals and negative numbers by hand is error-prone. This calculator keeps a running total and works with any real numbers.
How to use the Addition Calculator
- How many numbers?
- Number 1
- Number 2
- Number 3
- Number 4
- Number 5
- Number 6
- Number 7
- Number 8
- Number 9
- Number 10
Results update as you type, and everything is calculated in your browser.
How it works
The numbers are added in order. Addition is commutative and associative, so the order does not change the result.
Inputs explained
| Field | What to enter |
|---|---|
| How many numbers? | Choose one: 2, 3, 4, 5 … |
| Number 1 | A number |
| Number 2 | A number |
| Number 3 | A number |
| Number 4 | A number |
| Number 5 | A number |
| Number 6 | A number |
| Number 7 | A number |
| Number 8 | A number |
| Number 9 | A number |
| Number 10 | A number |
Example values
How the main result changes when Number 1 changes and everything else stays at the example values above:
| Number 1 | Sum |
|---|---|
| 625.38 | 1,014.775 |
| 938.06 | 1,327.4625 |
| 1,250.75 | 1,640.15 |
| 1,563.44 | 1,952.8375 |
| 1,876.13 | 2,265.525 |
| 2,501.5 | 2,890.9 |
Formula
Sum C = A₁ + A₂ + … + Aₙ
Worked example
Inputs — How many numbers?: 2; Number 1: 1,250.75; Number 2: 389.4.
Results — Sum = 1,640.15; Average = 820.075.
Key terms
- Addend
- A number being added.
- Sum
- The result of an addition.
Frequently asked questions
What are the parts of an addition called?
The numbers being added are addends and the result is the sum.
Does the order matter?
No – addition is commutative (a + b = b + a) and associative.
How do I add negative numbers?
Adding a negative is the same as subtracting its absolute value: 5 + (−8) = −3.
How do I check an addition?
Subtract one addend from the sum – you should get the other.