The CAS Registry Mumber 91146-88-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,1,1,4 and 6 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 91146-88: (7*9)+(6*1)+(5*1)+(4*4)+(3*6)+(2*8)+(1*8)=132 132 % 10 = 2 So 91146-88-2 is a valid CAS Registry Number.