diff --git a/README.md b/README.md
index bb2a49a..b88faee 100644
--- a/README.md
+++ b/README.md
@@ -104,7 +104,7 @@ obj.key
 
 You can get png file directly from Texture2D asset. Output object's class is `ChunkyPNG::Image`.
 
-Some basic texture formats (1--5, 7, 9, 13--20, 22, 62, and 63), ETC_RGB4 (34), ETC2 (45, 47), and ASTC (48--59) are available.
+Some basic texture formats (1–5, 7, 9, 13–20, 22, 62, and 63), ETC_RGB4 (34), ETC2 (45, 47), and ASTC (48–59) are available.
 
 ```ruby
 require 'mikunyan/decoders'