The CAS Registry Mumber 122313-80-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,2,3,1 and 3 respectively; the second part has 2 digits, 8 and 0 respectively. Calculate Digit Verification of CAS Registry Number 122313-80: (8*1)+(7*2)+(6*2)+(5*3)+(4*1)+(3*3)+(2*8)+(1*0)=78 78 % 10 = 8 So 122313-80-8 is a valid CAS Registry Number.