The CAS Registry Mumber 91524-12-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,1,5,2 and 4 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 91524-12: (7*9)+(6*1)+(5*5)+(4*2)+(3*4)+(2*1)+(1*2)=118 118 % 10 = 8 So 91524-12-8 is a valid CAS Registry Number.