The CAS Registry Mumber 82236-55-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,2,3 and 6 respectively; the second part has 2 digits, 5 and 5 respectively. Calculate Digit Verification of CAS Registry Number 82236-55: (7*8)+(6*2)+(5*2)+(4*3)+(3*6)+(2*5)+(1*5)=123 123 % 10 = 3 So 82236-55-3 is a valid CAS Registry Number.