Problem: find the greatest common factor ( gfc ) of 24 , 40 and 60 .
Rationale: we first write the prime factorization of each given number 24 = 2 × 2 × 2 × 3 = 23 * cubic * × 3 40 = 2 × 2 × 2 × 5 = 23 * cubic * × 5 60 = 2 × 2 × 3 × 5 = 22 * square * × 3 × 5 gfc = 22 * square * = 4 corect answer is d ) 4
annotated_formula: gcd(gcd(24, 40), 60)