How to memorize the days of the week much easier.
In order to help you understand it better, first of all, I´m going to give you both, cardinal and ordinal numbers.
1 (jedan) -- 1st prvi (m) / prva (f)/prvo (n)
2 (dva) -- 2nd drugi (m) / druga (f) / drugo (n)
3 (tri) -- 3rd treći (m) / treća (f) / treće (n)
4 (četiri)-- 4th četvrti (m) / četvrta(f) / četvrto (n)
5 (pet) -- 5th peti (m) / peta (f) / peto (n)
6 (šest)--- 6th šesti (m) / šesta (f) / šesto (n)
7 (sedam)-- 7th sedmi (m) / sedma (f) / sedmo (n)
8 (osam)--- 8th osmi (m) / osma (f) / osmo (n)
9 (devet)--- 9th deveti (m) / deveta (f) / deveto (n)
10 (deset)-- 10th deseti (m) / deseta (f) / deseto (n)
Sunday, week - nedelja
Monday - POnedeljak (this prefix PO is actually a preposition that can mean: after, on something, etc
In this case, Monday comes after Sunday and it indicates the beginning of the next week as well.
Tuesday - utorak
Wednesday - sreda (it comes from "sredina" which means medium. So, it indicates the middle of the week).
Thursday - četvtak (the root is ČET which indicates us it is the 4th day of the week).
Friday - petak (the root is the number 5 itself, so it indicates us it is the fifth day of the week).
Saturday - subota (it is the sixth day of the week. Plus, for Jewish people it is the the day they do not work and they call it "sabat")
Exercise:
So, what day of the week is today:
Koji je danas dan u nedelji?
You should say: "Today is .... - Danas je ..."
Koji je dan u nedelji bio juče / prekjuče? - What day of the week was yesterday, the day before yesterday?
You should say:
Juče/prekjuče je bio/bila ..... .
Yesterday/the day before yesterday was ....
Koji dan u nedelji će biti sutra / prekosutra?
What day of the week will be tomorrow/the day after tomorrow?
You should say:
Sutra/prekosutra će biti .....
Tomorrow/the day after tomorrow will be ....