The CAS Registry Mumber 122280-99-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,2,2,8 and 0 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 122280-99: (8*1)+(7*2)+(6*2)+(5*2)+(4*8)+(3*0)+(2*9)+(1*9)=103 103 % 10 = 3 So 122280-99-3 is a valid CAS Registry Number.