The CAS Registry Mumber 2569-69-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,5,6 and 9 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 2569-69: (6*2)+(5*5)+(4*6)+(3*9)+(2*6)+(1*9)=109 109 % 10 = 9 So 2569-69-9 is a valid CAS Registry Number.