The CAS Registry Mumber 76629-54-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,6,2 and 9 respectively; the second part has 2 digits, 5 and 4 respectively. Calculate Digit Verification of CAS Registry Number 76629-54: (7*7)+(6*6)+(5*6)+(4*2)+(3*9)+(2*5)+(1*4)=164 164 % 10 = 4 So 76629-54-4 is a valid CAS Registry Number.