The CAS Registry Mumber 108935-00-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,9,3 and 5 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 108935-00: (8*1)+(7*0)+(6*8)+(5*9)+(4*3)+(3*5)+(2*0)+(1*0)=128 128 % 10 = 8 So 108935-00-8 is a valid CAS Registry Number.