The CAS Registry Mumber 145513-54-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,5,5,1 and 3 respectively; the second part has 2 digits, 5 and 4 respectively. Calculate Digit Verification of CAS Registry Number 145513-54: (8*1)+(7*4)+(6*5)+(5*5)+(4*1)+(3*3)+(2*5)+(1*4)=118 118 % 10 = 8 So 145513-54-8 is a valid CAS Registry Number.