<ol>
<li>Variable in Apex
</li>
<li>Variable type
</li>
<li>Variable name
</li>
<li>Declare &amp; initialize a variable
</li>
<li>String, Integer, Decimal, Boolean, Date &amp; DateTime, Id variables, Null &amp; variables
</li>
</ol>

1. Variable in Apex
    
2. Variable type
    
3. Variable name
    
4. Declare & initialize a variable
    
5. String, Integer, Decimal, Boolean, Date & DateTime, Id variables, Null & variables

Apex - EP-01 : Basic concepts of programming in Salesforce Apex