The CAS Registry Mumber 5584-41-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,5,8 and 4 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 5584-41: (6*5)+(5*5)+(4*8)+(3*4)+(2*4)+(1*1)=108 108 % 10 = 8 So 5584-41-8 is a valid CAS Registry Number.