The CAS Registry Mumber 79918-36-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,9,1 and 8 respectively; the second part has 2 digits, 3 and 6 respectively. Calculate Digit Verification of CAS Registry Number 79918-36: (7*7)+(6*9)+(5*9)+(4*1)+(3*8)+(2*3)+(1*6)=188 188 % 10 = 8 So 79918-36-8 is a valid CAS Registry Number.