The CAS Registry Mumber 87774-69-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,7,7 and 4 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 87774-69: (7*8)+(6*7)+(5*7)+(4*7)+(3*4)+(2*6)+(1*9)=194 194 % 10 = 4 So 87774-69-4 is a valid CAS Registry Number.