diff --git a/modules/home/emacs.nix b/modules/home/emacs.nix
index 3836680..6951719 100644
--- a/modules/home/emacs.nix
+++ b/modules/home/emacs.nix
@@ -83,6 +83,7 @@ in {
           fontspec
           dvisvgm dvipng wrapfig # For Org-mode previews/export.
           amsmath # Essential for mathematics.
+          cancel # Cross out terms in math mode.
           spath3 # TikZ dependency?
           ulem hyperref
           capt-of