diff --git a/collects/typed-scheme/private/base-env-numeric.rkt b/collects/typed-scheme/private/base-env-numeric.rkt
index 3c3db19d..b709fbb7 100644
--- a/collects/typed-scheme/private/base-env-numeric.rkt
+++ b/collects/typed-scheme/private/base-env-numeric.rkt
@@ -46,7 +46,8 @@
   (define-for-syntax fx-op (cl->* (-Pos -Pos . -> . -PositiveFixnum)
                                   (-Nat -Nat . -> . -NonnegativeFixnum)
                                   (-Integer -Integer . -> . -Fixnum)))
-  (define-for-syntax fx-intop (-Integer -Integer . -> . -Fixnum))
+  (define-for-syntax fx-natop (cl->* (-Nat -Nat . -> . -NonnegativeFixnum)
+                                     (-Integer -Integer . -> . -Fixnum)))
   (define-for-syntax fx-unop (-Integer . -> . -Fixnum))
 
   (define-for-syntax real-comp (->* (list R R) R B))
@@ -57,6 +58,8 @@
            (-Nat -Pos . -> . -PositiveFixnum)
            (-Nat -Nat . -> . -NonnegativeFixnum)
            (-Integer -Integer . -> . -Fixnum)))
+  (define-for-syntax fx--type
+    (-Integer -Integer . -> . -Fixnum))
   (define-for-syntax fx=-type
     (cl->*
      (-> -Integer (-val 0) B : (-FS (-filter (-val 0) 0) -top))
@@ -473,11 +476,11 @@
 [unsafe-flimag-part (-InexactComplex . -> . -Flonum)]
 
 [unsafe-fx+ fx+-type]
-[unsafe-fx- fx-intop]
+[unsafe-fx- fx--type]
 [unsafe-fx* fx-op]
-[unsafe-fxquotient fx-intop]
-[unsafe-fxremainder fx-intop]
-[unsafe-fxmodulo fx-intop]
+[unsafe-fxquotient fx-natop]
+[unsafe-fxremainder fx-natop]
+[unsafe-fxmodulo fx-natop]
 [unsafe-fxabs (-Integer . -> . (Un -PositiveFixnum (-val 0)))]
 
 [unsafe-fxand fx-op]
@@ -498,11 +501,11 @@
 ;; scheme/fixnum
 
 [fx+ fx+-type]
-[fx- fx-intop]
+[fx- fx--type]
 [fx* fx-op]
-[fxquotient fx-intop]
-[fxremainder fx-intop]
-[fxmodulo fx-intop]
+[fxquotient fx-natop]
+[fxremainder fx-natop]
+[fxmodulo fx-natop]
 [fxabs (-Integer . -> . (Un -PositiveFixnum (-val 0)))]
 
 [fxand fx-op]
diff --git a/collects/typed-scheme/typecheck/tc-app.rkt b/collects/typed-scheme/typecheck/tc-app.rkt
index f00a8e29..8102b6c1 100644
--- a/collects/typed-scheme/typecheck/tc-app.rkt
+++ b/collects/typed-scheme/typecheck/tc-app.rkt
@@ -22,7 +22,7 @@
          (r:infer infer)
          '#%paramz
          (for-template
-          racket/unsafe/ops
+          racket/unsafe/ops racket/fixnum racket/flonum
           (only-in '#%kernel [apply k:apply])
           "internal-forms.rkt" scheme/base scheme/bool '#%paramz
           (only-in racket/private/class-internal make-object do-make-object)))
@@ -484,6 +484,13 @@
         [(subtype t -NonnegativeFixnum) (ret -Fixnum)]
         [(subtype t -ExactPositiveInteger) (ret -Nat)]
         [else (tc/funapp #'op #'(v arg2) (single-value #'op) (list (ret t) (single-value #'arg2)) expected)]))]
+    ;; idem for fx-
+    [(#%plain-app (~and op (~or (~literal fx-) (~literal unsafe-fx-))) v (~and arg2 ((~literal quote) 1)))
+     (add-typeof-expr #'arg2 (ret -PositiveFixnum))
+     (match-let ([(tc-result1: t) (single-value #'v)])
+       (cond
+        [(subtype t -ExactPositiveInteger) (ret -NonnegativeFixnum)]
+        [else (tc/funapp #'op #'(v arg2) (single-value #'op) (list (ret t) (single-value #'arg2)) expected)]))]
     ;; call-with-values
     [(#%plain-app call-with-values prod con)
      (match (tc/funapp #'prod #'() (single-value #'prod) null #f)