The CAS Registry Mumber 13768-00-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,7,6 and 8 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 13768-00: (7*1)+(6*3)+(5*7)+(4*6)+(3*8)+(2*0)+(1*0)=108 108 % 10 = 8 So 13768-00-8 is a valid CAS Registry Number.