The CAS Registry Mumber 98795-78-9 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, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 98795-78: (7*9)+(6*8)+(5*7)+(4*9)+(3*5)+(2*7)+(1*8)=219 219 % 10 = 9 So 98795-78-9 is a valid CAS Registry Number.