I am currently studying Aromatic compounds to include IUPAC naming, however am confused about when to use numbers to ide

[answerhappygod]

I am currently studying Aromatic compounds to include IUPACnaming, however am confused about when to use numbers to identifysubstituents vs when to use position (-ortho, -para, -meta). Whenthere are two substituents how do I know? Are there specific rulesfor which I use one vs the other?
For example, when studying problems from the back of my book Iguessed "m-chloroethylbenzene" for a compound but the cheggsolution told me it should be "1-chloro-3-ethylbenzene". HOWEVER,for the next question the correct answer was listed as"p-chlorotoluene" instead of "4-chloro-1-toluene".
When I googled it, I found both the m-chloro- and 1-chloro-listed frequently. So, my question being: are they both correct, oris there a specific condition under which I should use position vsnumbering?
Thank you!