The CAS Registry Mumber 79369-98-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,3,6 and 9 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 79369-98: (7*7)+(6*9)+(5*3)+(4*6)+(3*9)+(2*9)+(1*8)=195 195 % 10 = 5 So 79369-98-5 is a valid CAS Registry Number.