The CAS Registry Mumber 79396-89-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,3,9 and 6 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 79396-89: (7*7)+(6*9)+(5*3)+(4*9)+(3*6)+(2*8)+(1*9)=197 197 % 10 = 7 So 79396-89-7 is a valid CAS Registry Number.