From 009b2e6cd85ef3c5e246cca90325571d5ffb47f8 Mon Sep 17 00:00:00 2001
From: TheRealSpartacus <zachfears8@gmail.com>
Date: Sat, 10 Nov 2018 06:47:01 -0800
Subject: [PATCH] Adding content to article (#21484)

Saw this article was empty, decided to fill it
---
 .../mathematics/sigma-notation/index.md       | 27 +++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/guide/english/mathematics/sigma-notation/index.md b/guide/english/mathematics/sigma-notation/index.md
index 17b74d3ed0..a486592f22 100644
--- a/guide/english/mathematics/sigma-notation/index.md
+++ b/guide/english/mathematics/sigma-notation/index.md
@@ -3,13 +3,36 @@ title: Sigma Notation
 ---
 ## Sigma Notation
 
-This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/mathematics/sigma-notation/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+Sigma Notation is a mathematical shorthand for representing large sums.
 
-<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+Sigma Notation is as follows
 
+![alt text](https://github.com/TheRealSpartacus/sources/blob/master/SiGma.PNG "Sigma Notation")
 <!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->
+where *n* is the lower limit *k* is the upper limit and *a<sub>n</sub>* is the function you are summating
+
+To evaluate a sum in Sigma notation, you first plug in all integers from the *n* to *k* to *a<sub>n</sub>*, then add up all the results.
+
+For example :
+
+![alt text](https://github.com/TheRealSpartacus/sources/blob/master/Sigma%20Fig%201.PNG "Fig. 1")
+
+First, you plug all integers from *n* to *k* into *a<sub>n</sub>* :
+
+![alt text](https://github.com/TheRealSpartacus/sources/blob/master/Sigma%20Fig%202.PNG "Fig. 2")
+
+Second, you evaluate all instances of *a<sub>n</sub>* :
+
+![alt text](https://github.com/TheRealSpartacus/sources/blob/master/Sigma%20Fig%203.PNG "Fig. 3")
+
+Last, you add all the results up, leaving you with the value of the sigma :
+
+![alt text](https://github.com/TheRealSpartacus/sources/blob/master/Sigma%20Fig%204.PNG "Fig. 4")
 
 #### More Information:
 <!-- Please add any articles you think might be helpful to read before writing the article -->
 
+<a href="http://www.youtube.com/watch?feature=player_embedded&v=5jwXThH6fg4
+" target="_blank"><img src="http://img.youtube.com/vi/5jwXThH6fg4/0.jpg" 
+alt="IMAGE ALT TEXT HERE" width="240" height="180" border="10" /></a>