public function orderNumerically(a, b):Number{
	// Change a[0] & b[0] by a[i] & b[i]
	// (where i is the array index you want to use to sort the multidimensional array)
	var num1 = Number(a[0]);
	var num2 = Number(b[0]);
	if(num1<num2){
		return -1;
	}else if(num1>num2) {
		return 1;
	}else{
		return 0;
	}
}
the_array.sort(orderNumerically);

I have fixed and improved some code I found on the Internet

Sort multidimensional arrays in AS3 (numerically)

sort, array

ActionScript 3