Multiply float by int?

So I'm trying to create a score system that goes up by 100 every second. I get this error: "Only assignment, call, increment, decrement, and new object expressions can be used as a statement"

This is my code so far:

 using UnityEngine;
 using System.Collections;
 public class ScoreperSec : MonoBehaviour {
     public int startingScore = 0;
     public int currentScore = 0;
     public GUIText scoregui;
     private float time;
     private int score;
 void Update (){
         time+=Time.deltaTime;
         //currentScore += (int)time;
         print ((int)time);
         (int)time * 100 == score;
         scoregui.text = "Score: "+ score;
 }
 }