+ 
+ 
+ 
= 
+
+
+
=
\[2 + 4 + 6 + \cdots + 2n = n\left( {n + 1} \right)\]
\[ 1 + 3 + 5 + \cdots + \left( {2n - 1} \right) = n^2 \]
\[ 1^2 + 3^2 + 5^2 + \cdots + \left( {2n - 1} \right)^2 = \frac{1}{3}n\left( {4n^2 - 1} \right) \]
\[ 1^3 + 3^3 + 5^3 + \cdots + \left( {2n - 1} \right)^3 = n^2 \left( {2n^2 - 1} \right) \]