"<p>In this video we are going to talk about an important part about variables.<br /> The Variable Naming Rules: we cannot choose any name for a variable in Python since there are some restrictions.In this video we will try to cover the most important rules to prevent some invalid syntax errors.</p> <h3>Legal variable names:<code> </code></h3> <pre> <code>a = "Hello World!" a_b = "Hello World!" _a_b = "Hello World!" aB = "Hello World!" AB = "Hello World!" AB2 = "Hello World!"</code> </pre> <h3>Illegal variable names:<code> </code></h3> <pre> <code>2ab = "Hello World!" a-b = "Hello World!" a b = "Hello World!"</code></pre>"