The CAS Registry Mumber 79636-23-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,6,3 and 6 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 79636-23: (7*7)+(6*9)+(5*6)+(4*3)+(3*6)+(2*2)+(1*3)=170 170 % 10 = 0 So 79636-23-0 is a valid CAS Registry Number.