Without much doubt, the most complex, convoluted and confusing provision in the family-owned business exclusion (FOBE) is the pre-death requirement that the adjusted value of qualified family-owned business interests (plus pre-death gifts of family-owned business interests within the family) must exceed 50 percent of the decedent’s adjusted gross estate (with various modifications). The calculation involves a fraction with both the numerator and the denominator posing formidable problems of interpretation.