Question about 1,6-dichlorocyclohexene

[jonathanshi_1A]

On page 102 of the course reader, I'm confused why we wouldn't name it 1,6-dichloro-1-cyclohexene. In other organic molecules, we separate the substituent from the main carbon chain.

[April Z 1K]

In this case, I think it's because the 1 before cyclohexene is unnecessary (maybe not the best word to use). There are no functional groups like alcohol, so the double bond should automatically be assumed to be between C 1 and 2, and doesn't need to be specified. Though, I don't think points would be deducted for including it.