The CAS Registry Mumber 15089-10-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,5,0,8 and 9 respectively; the second part has 2 digits, 1 and 0 respectively. Calculate Digit Verification of CAS Registry Number 15089-10: (7*1)+(6*5)+(5*0)+(4*8)+(3*9)+(2*1)+(1*0)=98 98 % 10 = 8 So 15089-10-8 is a valid CAS Registry Number.