Randomly position Instantiated GameObject's

I've recently just enquired about randomly instantiating a gameobject, but now I've got a problem randomising there position, I've managed to get the position to randomise but this apples to all the instances. I want each instance to have its own random position.

var grass : GameObject;

function Start() {
     var grassNum = Random.Range(4, 10);
     var position = Vector3(Random.Range(-10, 10), 0, Random.Range(-10, 10));
     for (var i = 0; i < grassNum; i++){
        Instantiate(grass,position, Quaternion.identity);
     }
}

Thanks - C

If so you need to generate the position inside the for loop as well, to make sure it runs the same amount of times.

var grass : GameObject;

function Start() {
    var grassNum = Random.Range(4, 10);
    for (var i = 0; i < grassNum; i++){
        var position = Vector3(Random.Range(-10, 10), 0, Random.Range(-10, 10));
        Instantiate(grass,position, Quaternion.identity);
     }
}