diff --git a/README.md b/README.md
index eec9f3f..7616199 100644
--- a/README.md
+++ b/README.md
@@ -2,8 +2,13 @@
 
 Converts number like 1000 to 1K and 1500 to 1.5K.
 
+# Why a K letter?
+People occasionally represent the number in a non-standard notation by replacing the last three zeros of the general numeral with "k": for instance, 1k (or 1K) for 1,000.
+
 For now, to use FriendlyNumbers just add `FriendlyNumbers.swift` to your project.
 
+
+
 # Examples
 
 ```