IUPAC Naming Questions-Substituents and Bonds

[Conservation]

Hi all, couple of questions in the Official IUPAC naming rules for organic compounds:

1. How do I name organic molecules with both double/triple bonds and substituent? Do I name Both? For ex.: 2-Methyl-4-pentene vs. 2-Methylpentene?
2. If the double/triple bond and the substituent is in the same respective positions for either direction of the numbering, which is preferred? For example, for 2-Methyl-4-pentene (not sure if this is right yet, but...), is 4-Methyl-1-Pentene more correct as it has a numbering system with overall lower numbers? (4+1<2+4)

Thank you.

 

[DrClaude]

You must number the double bond, and the double bond has precedence when numbering. The correct name is therefore 4-methyl-1-pentene.