Why is this code not working?

I’ve started learning unity recently and I don’t understand why this code doesn’t work. Unity says there is an error in line 15 and a ; is expected. However, there is already a ; there.

You need to use New keyword for vector3 or in your case directly assign size vector to localscle

    private void Awake()
    {
        Vector3 size = transform.localScale + new Vector3(1f, 1f, 1f);

        transform.localScale = size;

        //OR 

        transform.localScale = new Vector3(size.x, size.y, size.z);

    }