Simple arithmetic in Set Theory

Question

For example if I plot number line and add $0 + 12$, then subtract $12 -12$ (if I wrote this in one line it would be: $(0+12)-12$), how it would be implemented in set theory? $A = \{x \in R\ |\ x \in [0,12]\}$ $([0] \cup A]) \setminus A = \emptyset$? Or mathematical operations can't touch first element ($(0,12]$)?

Answer 1

Define $A=\{1,2,3,4,5,6,7,8,9,10,11,12\}$

$0=|\emptyset|,12=|A|$, where the $|X|$ symbol means cardinality of the set $X$

$(0+12)-12$ means, in set operations, $$(A\cup\emptyset) \setminus A$$ which obviously gives $\emptyset$.