diff --git a/_config.yml b/_config.yml
index 013e477..22f7097 100644
--- a/_config.yml
+++ b/_config.yml
@@ -17,6 +17,11 @@ redcarpet:
   extensions: ["strikethrough"]
 
 collections:
+  math:
+    title: math
+    output: true
+    permalink: /math/:path/
+    path: /math
   programming:
     title: programming
     output: true
diff --git a/_posts/2017-09-07-primitive-living-0.md b/_posts/2017-09-07-primitive-living-0.md
index 1e35a9f..c53c8e2 100644
--- a/_posts/2017-09-07-primitive-living-0.md
+++ b/_posts/2017-09-07-primitive-living-0.md
@@ -2,7 +2,10 @@
 layout: post
 title:  "Primitive Living Lessons Learned, Episode 0"
 permalink: primitive-living-lessons-0/
-categories: life, primitive-living, travel
+categories:
+  - life
+  - primitive-living
+  - travel
 excerpt_separator: <!--more-->
 author: Mahdi
 ---
diff --git a/_posts/2017-09-24-diy-kindle-stand.md b/_posts/2017-09-24-diy-kindle-stand.md
index ff6482b..592fbc8 100644
--- a/_posts/2017-09-24-diy-kindle-stand.md
+++ b/_posts/2017-09-24-diy-kindle-stand.md
@@ -2,7 +2,9 @@
 layout: post
 title:  "DIY Cardboard Kindle Stand (for bed)"
 permalink: diy-cardboard-kindle-stand/
-categories: life, diy
+categories:
+  - life
+  - diy
 excerpt_separator: <!--more-->
 author: Mahdi
 ---
diff --git a/_posts/2017-09-27-typoclassopedia-exercise-answers.md b/_posts/2017-09-27-typoclassopedia-exercise-answers.md
index f110f8c..9bdb683 100644
--- a/_posts/2017-09-27-typoclassopedia-exercise-answers.md
+++ b/_posts/2017-09-27-typoclassopedia-exercise-answers.md
@@ -3,7 +3,9 @@ layout: post
 title:  "Typoclassopedia: Exercise solutions"
 date:   2017-09-27 
 permalink: typoclassopedia-exercise-solutions/
-categories: programming
+categories:
+  - programming
+  - math
 math: true
 toc: true
 author: Mahdi
diff --git a/math.html b/math.html
new file mode 100644
index 0000000..117fd7c
--- /dev/null
+++ b/math.html
@@ -0,0 +1,4 @@
+---
+layout: category
+category: math
+---