diff --git a/src/Bergamot/Rules.elm b/src/Bergamot/Rules.elm
index 68f5e8a..d2cb507 100644
--- a/src/Bergamot/Rules.elm
+++ b/src/Bergamot/Rules.elm
@@ -158,6 +158,15 @@ builtinRules t =
             Call "int" [Var output] ->
                 let rec i = interleave (suggest "BuiltinInt" (IntLit i) output) (lazy <| \_ -> rec (i+1))
                 in rec 0
+            Call "float" [FloatLit f] ->
+                MkProofTree { name = "BuiltinFloat", conclusion = t, premises = [] }
+                |> pure
+            Call "float" [Var output] ->
+                let rec f = interleave (suggest "BuiltinFloat" (FloatLit f) output) (lazy <| \_ -> rec (f+1))
+                in rec 0
+            Call "num" [tp] ->
+                interleave (builtinRules (Call "int" [tp])) (builtinRules (Call "float" [tp]))
+                |> map (\prem -> MkProofTree { name = "BuiltinNum", conclusion = t, premises = [prem] })
             Call "str" [StringLit s] ->
                 MkProofTree { name = "BuiltinStr", conclusion = t, premises = [] }
                 |> pure
@@ -171,12 +180,15 @@ builtinRules t =
                 pure (\_ _ -> MkProofTree { name = "BuiltinCall", conclusion = t, premises = [] })
                 |> apply (liftUnification unify (Var name) (StringLit <| encodeStr s))
                 |> apply (liftUnification unify (Var args) (List.foldr (\x xs -> Call "cons" [x, xs]) (Call "nil" []) ts))
-            Call "tostring" [IntLit i, Var output] ->
-                liftUnification unify (Var output) (StringLit (String.fromInt i))
-                |> map (\_ -> MkProofTree { name = "BuiltinToString", conclusion = t, premises = []})
-            Call "tostring" [Call s [], Var output] ->
-                liftUnification unify (Var output) (StringLit <| encodeStr s)
-                |> map (\_ -> MkProofTree { name = "BuiltinToString", conclusion = t, premises = []})
+            Call "tostring" [tp, Var output] ->
+                let
+                    suggestStr s = suggest "BuiltinToString" (StringLit s) output
+                in
+                    case tp of
+                        IntLit i -> suggestStr (String.fromInt i)
+                        FloatLit f -> suggestStr (String.fromFloat f)
+                        Call s [] -> suggestStr (encodeStr s)
+                        _ -> fail
             Call "escapestring" [StringLit s, Var output] ->
                 liftUnification unify (Var output) (StringLit (encodeStr s))
                 |> map (\_ -> MkProofTree { name = "BuiltinEscapeString", conclusion = t, premises = []})