The CAS Registry Mumber 85253-98-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,5,2,5 and 3 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 85253-98: (7*8)+(6*5)+(5*2)+(4*5)+(3*3)+(2*9)+(1*8)=151 151 % 10 = 1 So 85253-98-1 is a valid CAS Registry Number.