diff --git a/GNUmakefile b/GNUmakefile
index 094f820e..f8aa33dc 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -25,11 +25,12 @@ all: mes
 mes.o: mes.c
 mes.o: mes.c mes.environment.h mes.environment.i mes.symbols.i
 mes.o: define.c define.environment.h define.environment.i
+mes.o: math.c math.environment.h math.environment.i
 mes.o: quasiquote.c quasiquote.environment.h quasiquote.environment.i
 mes.o: type.c type.environment.h type.environment.i
 
 clean:
-	rm -f mes mes.o mes.environment.i mes.symbols.i mes.environment.h *.cat a.out
+	rm -f mes mes.o *.environment.i *.symbols.i *.environment.h *.cat a.out
 
 distclean: clean
 	rm -f .config.make
diff --git a/math.c b/math.c
new file mode 100644
index 00000000..a28f89b8
--- /dev/null
+++ b/math.c
@@ -0,0 +1,145 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * Mes --- Maxwell Equations of Software
+ * Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of Mes.
+ *
+ * Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+scm *
+greater_p (scm *x) ///((name . ">") (args . n))
+{
+  int n = INT_MAX;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      if (x->car->value >= n) return &scm_f;
+      n = x->car->value;
+      x = cdr (x);
+    }
+  return &scm_t;
+}
+
+scm *
+less_p (scm *x) ///((name . "<") (args . n))
+{
+  int n = INT_MIN;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      if (x->car->value <= n) return &scm_f;
+      n = x->car->value;
+      x = cdr (x);
+    }
+  return &scm_t;
+}
+
+scm *
+is_p (scm *x) ///((name . "=") (args . n))
+{
+  if (x == &scm_nil) return &scm_t;
+  assert (x->car->type == NUMBER);
+  int n = x->car->value;
+  x = cdr (x);
+  while (x != &scm_nil)
+    {
+      if (x->car->value != n) return &scm_f;
+      x = cdr (x);
+    }
+  return &scm_t;
+}
+
+scm *
+minus (scm *x) ///((name . "-") (args . n))
+{
+  scm *a = car (x);
+  assert (a->type == NUMBER);
+  int n = a->value;
+  x = cdr (x);
+  if (x == &scm_nil)
+    n = -n;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      n -= x->car->value;
+      x = cdr (x);
+    }
+  return make_number (n);
+}
+
+scm *
+plus (scm *x) ///((name . "+") (args . n))
+{
+  int n = 0;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      n += x->car->value;
+      x = cdr (x);
+    }
+  return make_number (n);
+}
+
+scm *
+divide (scm *x) ///((name . "/") (args . n))
+{
+  int n = 1;
+  if (x != &scm_nil) {
+    assert (x->car->type == NUMBER);
+    n = x->car->value;
+    x = cdr (x);
+  }
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      n /= x->car->value;
+      x = cdr (x);
+    }
+  return make_number (n);
+}
+
+scm *
+modulo (scm *a, scm *b)
+{
+  assert (a->type == NUMBER);
+  assert (b->type == NUMBER);
+  return make_number (a->value % b->value);
+}
+
+scm *
+multiply (scm *x) ///((name . "*") (args . n))
+{
+  int n = 1;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      n *= x->car->value;
+      x = cdr (x);
+    }
+  return make_number (n);
+}
+
+scm *
+logior (scm *x) ///((args . n))
+{
+  int n = 0;
+  while (x != &scm_nil)
+    {
+      assert (x->car->type == NUMBER);
+      n |= x->car->value;
+      x = cdr (x);
+    }
+  return make_number (n);
+}
diff --git a/mes.c b/mes.c
index 288c1db5..cba0d05b 100644
--- a/mes.c
+++ b/mes.c
@@ -65,6 +65,7 @@ scm temp_number = {NUMBER, .name="nul", .value=0};
 #include "type.environment.h"
 #include "define.environment.h"
 #include "quasiquote.environment.h"
+#include "math.environment.h"
 #include "mes.environment.h"
 
 scm *display_ (FILE* f, scm *x);
@@ -195,6 +196,7 @@ quasisyntax (scm *x)
 
 #include "type.c"
 #include "define.c"
+#include "math.c"
 #include "quasiquote.c"
 
 //Library functions
@@ -1156,132 +1158,6 @@ read_env (scm *a)
   return readword (getchar (), 0, a);
 }
 
-scm *
-greater_p (scm *x) ///((name . ">") (args . n))
-{
-  int n = INT_MAX;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      if (x->car->value >= n) return &scm_f;
-      n = x->car->value;
-      x = cdr (x);
-    }
-  return &scm_t;
-}
-
-scm *
-less_p (scm *x) ///((name . "<") (args . n))
-{
-  int n = INT_MIN;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      if (x->car->value <= n) return &scm_f;
-      n = x->car->value;
-      x = cdr (x);
-    }
-  return &scm_t;
-}
-
-scm *
-is_p (scm *x) ///((name . "=") (args . n))
-{
-  if (x == &scm_nil) return &scm_t;
-  assert (x->car->type == NUMBER);
-  int n = x->car->value;
-  x = cdr (x);
-  while (x != &scm_nil)
-    {
-      if (x->car->value != n) return &scm_f;
-      x = cdr (x);
-    }
-  return &scm_t;
-}
-
-scm *
-minus (scm *x) ///((name . "-") (args . n))
-{
-  scm *a = car (x);
-  assert (a->type == NUMBER);
-  int n = a->value;
-  x = cdr (x);
-  if (x == &scm_nil)
-    n = -n;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      n -= x->car->value;
-      x = cdr (x);
-    }
-  return make_number (n);
-}
-
-scm *
-plus (scm *x) ///((name . "+") (args . n))
-{
-  int n = 0;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      n += x->car->value;
-      x = cdr (x);
-    }
-  return make_number (n);
-}
-
-scm *
-divide (scm *x) ///((name . "/") (args . n))
-{
-  int n = 1;
-  if (x != &scm_nil) {
-    assert (x->car->type == NUMBER);
-    n = x->car->value;
-    x = cdr (x);
-  }
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      n /= x->car->value;
-      x = cdr (x);
-    }
-  return make_number (n);
-}
-
-scm *
-modulo (scm *a, scm *b)
-{
-  assert (a->type == NUMBER);
-  assert (b->type == NUMBER);
-  return make_number (a->value % b->value);
-}
-
-scm *
-multiply (scm *x) ///((name . "*") (args . n))
-{
-  int n = 1;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      n *= x->car->value;
-      x = cdr (x);
-    }
-  return make_number (n);
-}
-
-scm *
-logior (scm *x) ///((args . n))
-{
-  int n = 0;
-  while (x != &scm_nil)
-    {
-      assert (x->car->type == NUMBER);
-      n |= x->car->value;
-      x = cdr (x);
-    }
-  return make_number (n);
-}
-
 scm *
 add_environment (scm *a, char const *name, scm *x)
 {
@@ -1308,6 +1184,7 @@ mes_environment () ///((internal))
   a = cons (cons (&symbol_quote, &scm_quote), a);
   a = cons (cons (&symbol_syntax, &scm_syntax), a);
 
+#include "math.environment.i"
 #include "mes.environment.i"
 #include "define.environment.i"
 #include "type.environment.i"