The CAS Registry Mumber 55282-82-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,5,2,8 and 2 respectively; the second part has 2 digits, 8 and 2 respectively. Calculate Digit Verification of CAS Registry Number 55282-82: (7*5)+(6*5)+(5*2)+(4*8)+(3*2)+(2*8)+(1*2)=131 131 % 10 = 1 So 55282-82-1 is a valid CAS Registry Number.