The CAS Registry Mumber 94017-98-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,0,1 and 7 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 94017-98: (7*9)+(6*4)+(5*0)+(4*1)+(3*7)+(2*9)+(1*8)=138 138 % 10 = 8 So 94017-98-8 is a valid CAS Registry Number.