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Kürschák Math Competition
1967 Kurschak Competition
1
1
Part of
1967 Kurschak Competition
Problems
(1)
difference of any two elements of set of integers A also belongs to A
Source: 1967 Hungary - Kürschák Competition p1
10/11/2022
A
A
A
is a set of integers which is closed under addition and contains both positive and negative numbers. Show that the difference of any two elements of
A
A
A
also belongs to
A
A
A
.
number theory