The CAS Registry Mumber 132454-21-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,4,5 and 4 respectively; the second part has 2 digits, 2 and 1 respectively. Calculate Digit Verification of CAS Registry Number 132454-21: (8*1)+(7*3)+(6*2)+(5*4)+(4*5)+(3*4)+(2*2)+(1*1)=98 98 % 10 = 8 So 132454-21-8 is a valid CAS Registry Number.