The CAS Registry Mumber 74629-77-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,6,2 and 9 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 74629-77: (7*7)+(6*4)+(5*6)+(4*2)+(3*9)+(2*7)+(1*7)=159 159 % 10 = 9 So 74629-77-9 is a valid CAS Registry Number.