diff --git a/lib/compiler/emit.ml b/lib/compiler/emit.ml
index 9ae847a..d8a83e2 100644
--- a/lib/compiler/emit.ml
+++ b/lib/compiler/emit.ml
@@ -202,3 +202,4 @@ let compile (exprs : expression list) (tbl : (int * expression) SymbolTable.t) =
 let compile_src src =
   let* (exprs, tbl) = Scope_analysis.of_src src in
   compile exprs tbl
+
diff --git a/lib/compiler/scope_analysis.ml b/lib/compiler/scope_analysis.ml
index 1bf3e87..100e859 100644
--- a/lib/compiler/scope_analysis.ml
+++ b/lib/compiler/scope_analysis.ml
@@ -57,8 +57,8 @@ type expression =
  *)
 let default_global_table =
   SymbolTable.of_list [
-      ("print", (0, Native 0));
-      ("add", (1, Native 1))
+      ("PRINT", (0, Native 0));
+      ("ADD", (1, Native 1))
     ]
 
 (* extract all defined global symbols, given the top-level expressions
diff --git a/lib/vm/native.ml b/lib/vm/native.ml
index d9d0832..ed16107 100644
--- a/lib/vm/native.ml
+++ b/lib/vm/native.ml
@@ -5,12 +5,38 @@
  *)
 open Types
 
+type numeric_val =
+  | NInt of int
+  | NDouble of float
+
+let to_numeric = function
+  | Int x -> NInt x
+  | Double x -> NDouble x
+  | v -> failwith ((print_value v) ^ " is not a numeric value")
+let of_numeric = function
+  | NInt x -> Int x
+  | NDouble x -> Double x
+let numeric_add = function
+  | NInt x -> (function
+               | NInt y -> NInt (x+y)
+               | NDouble y -> NDouble ((float_of_int x) +. y))
+  | NDouble x -> (function
+                  | NInt y -> NDouble (x+.(float_of_int y))
+                  | NDouble y -> NDouble (x+.y))
+
+
 let builtin_print (v : Types.value ref list) =
   List.iter (fun r -> print_endline (print_value !r)) v;
   Types.Nil
 
+
+
+let builtin_add (vs : Types.value ref list) =
+  of_numeric (List.fold_left numeric_add (NInt 0) (List.map (fun r -> to_numeric !r) vs))
+
 let table = [|
-    builtin_print
+    builtin_print;
+    builtin_add
   |]
 
 
diff --git a/lib/vm/vm.ml b/lib/vm/vm.ml
index 6690121..27350a7 100644
--- a/lib/vm/vm.ml
+++ b/lib/vm/vm.ml
@@ -52,7 +52,7 @@ let rec do_apply state arg_count =
   | _ -> failwith "Cannot apply non-closure object"
 
 and interpret state =
-  (*trace state; (* For debug use *)*)
+  (*trace state; (*For debug use only*)*)
   let i = state.i in
   state.i <- i + 1;
   (match state.instrs.(i) with