The CAS Registry Mumber 89859-79-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,8,5 and 9 respectively; the second part has 2 digits, 7 and 9 respectively. Calculate Digit Verification of CAS Registry Number 89859-79: (7*8)+(6*9)+(5*8)+(4*5)+(3*9)+(2*7)+(1*9)=220 220 % 10 = 0 So 89859-79-0 is a valid CAS Registry Number.