diff --git a/zip-0032.rst b/zip-0032.rst
index 2a542fd7..e35140b6 100644
--- a/zip-0032.rst
+++ b/zip-0032.rst
@@ -111,7 +111,7 @@ Implementors should note that this ZIP is consistently little-endian (in keeping
 specification), which is the opposite of BIP 32.
 
 We adapt the path notation of BIP 32 [#bip-0032]_ to describe shielded HD paths, using apostrophes to
-indicate hardened derivation as in BIP 44 [#bip-0044]_:
+indicate hardened derivation (i' = i + 2\ :sup:`31`\ ) as in BIP 44 [#bip-0044]_:
 
 - CDKsk(CDKsk(CDKsk(m\ :sub:`Sprout`\ , a'), b), c) is written as m\ :sub:`Sprout` / a' / b / c
 - CDKfvk(CDKfvk(CDKfvk(M\ :sub:`Sapling`\ , a), b), c) is written as M\ :sub:`Sapling` / a / b / c