Radionica engleski 18.

I follow the Effortless English five day training method.
I practice every unit for at least five days.

I follow the Effortless English five day training method. = "five-day training method" here is the single event "five-day training method". Five day = here is an adverb.

I practice every unit for at least five days. = "five days" here are "at least five" separate events, how many days.