The CAS Registry Mumber 69974-64-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,9,9,7 and 4 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 69974-64: (7*6)+(6*9)+(5*9)+(4*7)+(3*4)+(2*6)+(1*4)=197 197 % 10 = 7 So 69974-64-7 is a valid CAS Registry Number.