The CAS Registry Mumber 79351-97-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,3,5 and 1 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 79351-97: (7*7)+(6*9)+(5*3)+(4*5)+(3*1)+(2*9)+(1*7)=166 166 % 10 = 6 So 79351-97-6 is a valid CAS Registry Number.