The CAS Registry Mumber 74845-58-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,8,4 and 5 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 74845-58: (7*7)+(6*4)+(5*8)+(4*4)+(3*5)+(2*5)+(1*8)=162 162 % 10 = 2 So 74845-58-2 is a valid CAS Registry Number.