“…The triangular fuzzy number [2,20,28], which is defined as a fuzzy set in R and characterized by an ordered triple u = (a, b, c) ∈ R 3 with a ≤ b ≤ c such that u (r) = a + (b − a) r and ū (r) = c − (c − b) r, are the endpoints of r−level sets for all r ∈ [0, 1] is a popular fuzzy number:…”