The CAS Registry Mumber 98795-81-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,8,7,9 and 5 respectively; the second part has 2 digits, 8 and 1 respectively. Calculate Digit Verification of CAS Registry Number 98795-81: (7*9)+(6*8)+(5*7)+(4*9)+(3*5)+(2*8)+(1*1)=214 214 % 10 = 4 So 98795-81-4 is a valid CAS Registry Number.