The CAS Registry Mumber 35263-89-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,5,2,6 and 3 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 35263-89: (7*3)+(6*5)+(5*2)+(4*6)+(3*3)+(2*8)+(1*9)=119 119 % 10 = 9 So 35263-89-9 is a valid CAS Registry Number.