diff --git a/4-data-analytics.md b/4-data-analytics.md
index 85cc28d..b66f6b0 100644
--- a/4-data-analytics.md
+++ b/4-data-analytics.md
@@ -343,7 +343,7 @@
 
 - Create new features from existing ones, thus increasing predictive power
 - Takes the Cartesian product of existing features
-    - $A\times B=\{(a,b)\mid a\in A\ {\mbox{ and }}\ b\in B\}.$
+    - $A\times B=\{(a,b), a \in A \ and\  b\in B\}.$
 - Has uses when data is not linerarly separable
 - Deciding which feature to cross:
     - Use expertise