diff --git a/pmap.scrbl b/pmap.scrbl
index 0c37eb4..036f0b6 100644
--- a/pmap.scrbl
+++ b/pmap.scrbl
@@ -5,6 +5,8 @@
                     racket/base
                     racket/future
                     racket/place
+                    racket/fixnum
+                    math
                     racket/runtime-path]]
 
 @title{pmap}
diff --git a/pmapp_worker.rkt b/pmapp_worker.rkt
index 0afa402..d27169a 100644
--- a/pmapp_worker.rkt
+++ b/pmapp_worker.rkt
@@ -3,8 +3,8 @@
 (define worker-namespace
  (parameterize ((current-namespace (make-base-namespace)))
   (namespace-require 'racket)
-   (namespace-require 'racket/flonum)
-   (namespace-require 'racket/fixnum)
+    (namespace-require 'math)
+    (namespace-require 'racket/fixnum)
   (current-namespace)))
  
 (eval 'force worker-namespace) ; -> #<procedure:force>