diff --git a/users/wpcarro/emacs/pkgs/math/default.nix b/users/wpcarro/emacs/pkgs/math/default.nix
new file mode 100644
index 000000000..9167d61d4
--- /dev/null
+++ b/users/wpcarro/emacs/pkgs/math/default.nix
@@ -0,0 +1,30 @@
+{ pkgs, depot, ... }:
+
+let
+  math = pkgs.callPackage
+    ({ emacsPackages }:
+      emacsPackages.trivialBuild {
+        pname = "math";
+        version = "1.0.0";
+        src = ./math.el;
+        packageRequires =
+          (with emacsPackages; [
+            dash
+          ]) ++
+          (with depot.users.wpcarro.emacs.pkgs; [
+            maybe
+          ]);
+      })
+    { };
+
+  emacs = (pkgs.emacsPackagesFor pkgs.emacs28).emacsWithPackages (epkgs: [
+    math
+  ]);
+in
+math.overrideAttrs (_old: {
+  doCheck = true;
+  checkPhase = ''
+    ${emacs}/bin/emacs -batch \
+      -l ert -l ${./tests.el} -f ert-run-tests-batch-and-exit
+  '';
+})
diff --git a/users/wpcarro/emacs/.emacs.d/wpc/math.el b/users/wpcarro/emacs/pkgs/math/math.el
similarity index 100%
rename from users/wpcarro/emacs/.emacs.d/wpc/math.el
rename to users/wpcarro/emacs/pkgs/math/math.el
diff --git a/users/wpcarro/emacs/pkgs/math/tests.el b/users/wpcarro/emacs/pkgs/math/tests.el
new file mode 100644
index 000000000..ef3430c91
--- /dev/null
+++ b/users/wpcarro/emacs/pkgs/math/tests.el
@@ -0,0 +1,25 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'ert)
+(require 'math)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Tests
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(ert-deftest math-mod ()
+  (should (= 0 (math-mod 9 3)))
+  (should (= 4 (math-mod 9 5))))
+
+(ert-deftest math-exp ()
+  (should (= 9 (math-exp 3 2)))
+  (should (= 8 (math-exp 2 3))))
+
+(ert-deftest math-round ()
+  (should (= 10 (math-round 9.5)))
+  (should (= 9 (math-round 9.45))))
+
+(ert-deftest math-floor ()
+  (should (= 9 (math-floor 9.5))))