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Ahhh! Maths Union Sets problem!! Grrr

I'm doingf this exercise in a complementary textbook and i'm so idiotic i don't know how to do this question.
It's the last one in the chapter, maybe indicating it is difficult but i don't understand!
What is
(0,1) U {1,2} U [2,3]

Note the 3 dif. brackets... it's why i can't do this Q.
Please help and explain!!

Where U = Union = Or
So the first brackets are open sets, the middle a finite and the third a closed. I don't understand how that influences, cheers!

Reply 1

IrrationalNumber

Wrong forum. If we have (0,1) that's the same as saying everything in between 0 and 1 not inclusive. If we have [0,1) that means everything in between 0 and 1 including 0 but not 1. If we have [0,1] that means everything in between 0 and 1 including 0 and 1. If we have {0,1} that means just 0 and 1 (e.g. 1/2 is not in {0,1}).