The CAS Registry Mumber 79560-97-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,5,6 and 0 respectively; the second part has 2 digits, 9 and 7 respectively. Calculate Digit Verification of CAS Registry Number 79560-97: (7*7)+(6*9)+(5*5)+(4*6)+(3*0)+(2*9)+(1*7)=177 177 % 10 = 7 So 79560-97-7 is a valid CAS Registry Number.