Try to improve grammar further.
diff --git a/Doc/howto/doanddont.tex b/Doc/howto/doanddont.tex
index 56fd8ea..a105ca1 100644
--- a/Doc/howto/doanddont.tex
+++ b/Doc/howto/doanddont.tex
@@ -288,7 +288,7 @@
There are also many useful builtin functions people seem not to be
aware of for some reason: \function{min()} and \function{max()} can
find the minimum/maximum of any sequence with comparable semantics,
-for example, yet many people write they own
+for example, yet many people write their own
\function{max()}/\function{min()}. Another highly useful function is
\function{reduce()}. A classical use of \function{reduce()}
is something like