The CAS Registry Mumber 98796-27-1 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 6 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 98796-27: (7*9)+(6*8)+(5*7)+(4*9)+(3*6)+(2*2)+(1*7)=211 211 % 10 = 1 So 98796-27-1 is a valid CAS Registry Number.