diff --git a/lib/pure/math.nim b/lib/pure/math.nim
index 79a8675a60..54f5bc33ef 100644
--- a/lib/pure/math.nim
+++ b/lib/pure/math.nim
@@ -48,6 +48,8 @@
 ## * `mersenne module<mersenne.html>`_ for Mersenne twister random number generator
 ## * `stats module<stats.html>`_ for statistical analysis
 ## * `strformat module<strformat.html>`_ for formatting floats for print
+## * `system module<system.html>`_ Some very basic and trivial math operators
+##   are on system directly, to name a few ``shr``, ``shl``, ``xor``, ``clamp``, etc.
 
 
 include "system/inclrtl"