Question:
Show that the set of letters needed to spell "CATARACT" and the set of letters needed to spell "TRACT" are equal.
Solution:
Letters required to spell CATARACT are {C, A, T, R}. Let this set be denoted as E.
E = {C, A, T, R}
Letters required to spell TRACT are {T, R, A, C}. Let this set be denoted as F.
F = {T, R, A, C}
The two sets E & F are equal because every element of E is a member of F & every element of F is a member of E.