diff --git a/Ubuntu-Build.md b/Ubuntu-Build.md
index 28aa190..1292dcc 100644
--- a/Ubuntu-Build.md
+++ b/Ubuntu-Build.md
@@ -10,7 +10,8 @@ make
 ```
 
 ### gcc 7.1
-Optionally you can use gcc 7 to small performance increase.
+Optionally you can use gcc 7 to small performance increase.<br>
+If command `add-apt-repository` not found install `software-properties-common` first.
 ```bash
 sudo add-apt-repository ppa:jonathonf/gcc-7.1
 sudo apt-get update