diff --git a/Makefile b/Makefile
index ff4d473331d9a4eaaac3d654e5263ce08d578954..30f39507dd1de40d8328e412a88041eebbd9c13f 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@ STYLES := css/tufte-css/tufte.css \
 	css/tufte-extra.css
 
 OPTIONS = --toc
+OPTIONS += --filter=pandoc-numbering
 OPTIONS += --filter=pandoc-crossref
 
 PDFOPTIONS = --highlight-style kate