**Tell us what’s happening:**

Describe your issue in detail here.

can someone descript this code line . where a and b come from …where does the value take from

```
**Your code so far**
```

```
const sum = (x, y, z) => {
const args = [x, y, z];
this line only ==> return args.reduce((a, b) => a + b, 0); <==
}
```

```
**Your browser information:**
```

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36 Edg/92.0.902.73`

**Challenge:** Use the Rest Parameter with Function Parameters

**Link to the challenge:**