The CAS Registry Mumber 98632-34-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,8,6,3 and 2 respectively; the second part has 2 digits, 3 and 4 respectively. Calculate Digit Verification of CAS Registry Number 98632-34: (7*9)+(6*8)+(5*6)+(4*3)+(3*2)+(2*3)+(1*4)=169 169 % 10 = 9 So 98632-34-9 is a valid CAS Registry Number.