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# +(_:_:)

Adds two values and produces their sum.

```
static func + (a: Int128, b: Int128) -> Int128
```

## Discussion

The addition operator (`+`) calculates the sum of its two arguments. For
example:

```
1 + 2                   // 3
-10 + 15                // 5
-15 + -5                // -20
21.5 + 3.25             // 24.75
```

You cannot use `+` with arguments of different types. To add values of
different types, convert one of the values to the other value’s type.

```
let x: Int8 = 21
let y: Int = 1000000
Int(x) + y              // 1000021
```

---

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