The CAS Registry Mumber 90461-82-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,4,6 and 1 respectively; the second part has 2 digits, 8 and 2 respectively. Calculate Digit Verification of CAS Registry Number 90461-82: (7*9)+(6*0)+(5*4)+(4*6)+(3*1)+(2*8)+(1*2)=128 128 % 10 = 8 So 90461-82-8 is a valid CAS Registry Number.