error CS8025: Parsing error: dont know what to do here

The problem was where you tried to accumulate n with a product of the variable a, Time.deltaTime, and dir. You mistyped deltaTime as delraTime.

 using UnityEngine;
 using System.Collections;
 
 public class playercontroller : MonoBehaviour {
     //player handling 
     public float speed = 8; 
     public float acceleration = 12;
 
     private float CurrentSpeed; 
     private float targetSpeed; 
     private Vector2 amountToMove;
 
     private playerphysics playerphysics;
 
     // Use this for initialization
     void Start () {
         playerphysics = GetComponent <playerphysics>();
     }
      
     // Update is called once per frame
     void Update () {
         targetSpeed = Input.GetAxisRow("Horizontal") *speed;
         CurrentSpeed = IncrementTowards(currentSpeed,targetSpeed,acceleration);
     } 
     
     // increase n towards target by speed 
     private float IncrementTowards(float n, float target , float a) 
     { 
         if (n== target)
         { 
             return n; 
         } 
         else
         { 
             float dir = Mathf .Sign(target - n); 
             //must n be increased or decreased to get closer to target 
             n+= a * Time.deltaTime * dir; 
             return (dir == Mathf. Sign(target-n)) ? n : target; //if n has now passed target then return target,otherwise return n 
         } 
     }
 }