diff --git a/doc/modules/naive_bayes.rst b/doc/modules/naive_bayes.rst
index 4c7f45ab4f276..216e0880dd3e3 100644
--- a/doc/modules/naive_bayes.rst
+++ b/doc/modules/naive_bayes.rst
@@ -149,7 +149,7 @@ The decision rule for Bernoulli Naive Bayes is based on
 
 .. math::
 
-    P(x_i \mid y) = P(i \mid y) x_i \times (1 - P(i \mid y)) (1 - x_i)
+    P(x_i \mid y) = P(i \mid y) x_i + (1 - P(i \mid y)) (1 - x_i)
 
 which differs from multinomial NB's rule
 in that it explicitly penalizes the non-occurrence of a feature :math:`i`