# E0223

Operator not defined for its operand's type: arithmetic and ordering need numbers (`+` is not for strings), unary `-` needs a signed number, `..` needs integers.

**Machine-applicable fix:** none.

## Example

This program fails with `E0223`.

```oska
fn main() {
    let text = "a" + "b"
}
```

## Fixed

The same program, fixed.

```oska
fn main() {
    let a = "a"
    let b = "b"
    let text = "{a}{b}"
}
```

Listed in the [checker notes](/checker.md#e0223). `oskac explain E0223` prints this entry offline.