diff --git a/education/math/MATH1220 (calc II)/Sequences.md b/education/math/MATH1220 (calc II)/Sequences.md
index 65ae417..69f6f18 100644
--- a/education/math/MATH1220 (calc II)/Sequences.md	
+++ b/education/math/MATH1220 (calc II)/Sequences.md	
@@ -39,3 +39,12 @@ Remember, L'Hospital's rule states that:
 
 # Series
 Vocabulary: A **series** is another name for a sum of numbers. 
+
+## Properties
+You can break a series into *partial sums*:
+$$\sum_{n=1}^\infty a_n = a_1 + 1_2 + a_3 + ...$$
+Given the above series, we can define the following:
+- $S_1 = a_1 = \sum_{i=1}^\infty a_i$
+- $S_2 = a_1 + a_2 = \sum_{i=1}^2 a_i$ 
+- $S_n = a_1 + a_2 + ... = \sum_{i=1}^n a_i$
+- 
\ No newline at end of file