The CAS Registry Mumber 41451-86-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,1,4,5 and 1 respectively; the second part has 2 digits, 8 and 6 respectively. Calculate Digit Verification of CAS Registry Number 41451-86: (7*4)+(6*1)+(5*4)+(4*5)+(3*1)+(2*8)+(1*6)=99 99 % 10 = 9 So 41451-86-9 is a valid CAS Registry Number.