The CAS Registry Mumber 98288-19-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,8,2,8 and 8 respectively; the second part has 2 digits, 1 and 9 respectively. Calculate Digit Verification of CAS Registry Number 98288-19: (7*9)+(6*8)+(5*2)+(4*8)+(3*8)+(2*1)+(1*9)=188 188 % 10 = 8 So 98288-19-8 is a valid CAS Registry Number.