Math2 ActionScript functions

Some math function are simple to write but often very useful in many situations. Here is part of flanture math2 actionscript library.

sum - sum of all numbers between l and h
prod - product of all numbers between l and h
sumAr - sum of all array elements

static function sumAr(a:Array):Number {
   var s:Number = 0;
   for(var i=0;i < a.length;i+=1){
      s=s+a[i];
   }
   return s;
}

prodAr - product of all array elements

static function prodAr(a:Array):Number {
   var p:Number = 1;
   for(var i=0;i < a.length;i+=1){
      p=p*a[i];
   }
   return p;
}

If any of array elements is zero, last function is zero, so:

prodArIZ - product of all array elements, zeros ignored

static function prodArIZ(a:Array):Number {
   var p:Number = 1;
   for(var i=0;i < a.length;i+=1){
      if(a[i]!=0){
         p=p*a[i];
      }
   }
   return p;
}

Homework for newbies: write function that returns all prime numbers between 1 and n?