The CAS Registry Mumber 34884-36-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,4,8,8 and 4 respectively; the second part has 2 digits, 3 and 6 respectively. Calculate Digit Verification of CAS Registry Number 34884-36: (7*3)+(6*4)+(5*8)+(4*8)+(3*4)+(2*3)+(1*6)=141 141 % 10 = 1 So 34884-36-1 is a valid CAS Registry Number.