[Tex/LaTex] How to insert text inside the aligned environment

Question

I often need to insert text and breaks in between equations but it's too cumbersome to type aligned again from beginning. What can I do to insert text inside the aligned environment ?

Also, is there any difference between align and aligned ? The former gives compile errors on my computer .

Answer 1

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
\sqrt{|a_{11} + b_{11} + \dots a_{nn} + a_{nn}|} & \leq \sqrt{|a_{11} + \dots + a_{nn}|} + \sqrt{|b_{11} + \dots + b_{nn}|}\\
 x &= \sqrt{|a_{11} + b_{11} + \dots a_{nn} + a_{nn}|} \notag\\ 
 y &= \sqrt{|a_{11} + \dots + a_{nn}|} \notag\\
 z &= \sqrt{|b_{11} + \dots + b_{nn}|}\notag\\
x & \leq  y + z  \notag\\
&= Square~{} each~{} element ~{}x, ~{}y ~{}and~{} z~{}and ~{} compute
\end{align}
\end{document}