The CAS Registry Mumber 1340-69-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,3,4 and 0 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1340-69: (6*1)+(5*3)+(4*4)+(3*0)+(2*6)+(1*9)=58 58 % 10 = 8 So 1340-69-8 is a valid CAS Registry Number.