diff --git a/source/calculus/notations.rst b/source/calculus/notations.rst
new file mode 100644
index 0000000..adc7730
--- /dev/null
+++ b/source/calculus/notations.rst
@@ -0,0 +1,21 @@
+Differentiation Notations
+================================
+
+
+Leibniz's Notation
+-------------------
+https://www.me.psu.edu/cimbala/me420/Homework/dydx_quotient_article.html
+
+Lagrange's Notation
+-------------------
+Also cal prime notation
+
+Newton's Notation
+-------------------
+
+
+.. note::
+ These notes are inspired from `this page `__
+
+
+
diff --git a/source/calculus/ode.rst b/source/calculus/ode.rst
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+Ordinary Differential Equations
+================================
+
+- An Ordinary Differential Equations (ODE) is a differential equation that involves a single independant variable and its derivatives.
+
+- The order of a ODE is define as the order of the highest derivative that occurs in the equation.
+
+`Original Source `__
+
+.. note::
+ When working with differential equations with often use the Lagrange's notation (see :doc:`notations`).
+
diff --git a/source/index.rst b/source/index.rst
index fbbaf3c..1b6d9a8 100644
--- a/source/index.rst
+++ b/source/index.rst
@@ -40,6 +40,14 @@ Welcome to ScienceNotes's documentation!
electronics/superposition.rst
electronics/thevnort.rst
+.. toctree::
+ :maxdepth: 2
+ :numbered:
+ :caption: Calculus
+
+ calculus/notations.rst
+ calculus/ode.rst
+
Indices and tables
==================