# Addition Calculator

URL: https://speedycalculator.com/calculators/math/addition/
Last updated: 2026-10-30

> The addition calculator adds up to ten numbers – whole numbers, decimals or negatives – and shows the running total.

## Inputs

- How many numbers?
- Number 1
- Number 2
- Number 3
- Number 4
- Number 5
- Number 6
- Number 7
- Number 8
- Number 9
- Number 10

## Results

- Sum
- Average

## Formula

```
Sum C = A₁ + A₂ + … + Aₙ
```

## Explanation

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

FieldWhat to enterHow many numbers?Choose one: 2, 3, 4, 5 …Number 1A numberNumber 2A numberNumber 3A numberNumber 4A numberNumber 5A numberNumber 6A numberNumber 7A numberNumber 8A numberNumber 9A numberNumber 10A number

### Example values

How the main result changes when **Number 1** changes and everything else stays at the example values above:

Number 1Sum625.381,014.775938.061,327.46251,250.751,640.151,563.441,952.83751,876.132,265.5252,501.52,890.9

## 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.

## FAQ

**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.


## Sources

- [OpenStax – Prealgebra 2e](https://openstax.org/details/books/prealgebra-2e)
- [OpenStax – Contemporary Mathematics](https://openstax.org/details/books/contemporary-mathematics)