The CAS Registry Mumber 122324-23-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,2,3,2 and 4 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 122324-23: (8*1)+(7*2)+(6*2)+(5*3)+(4*2)+(3*4)+(2*2)+(1*3)=76 76 % 10 = 6 So 122324-23-6 is a valid CAS Registry Number.