The CAS Registry Mumber 63186-23-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,3,1,8 and 6 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 63186-23: (7*6)+(6*3)+(5*1)+(4*8)+(3*6)+(2*2)+(1*3)=122 122 % 10 = 2 So 63186-23-2 is a valid CAS Registry Number.