The CAS Registry Mumber 949595-91-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 9,4,9,5,9 and 5 respectively; the second part has 2 digits, 9 and 1 respectively. Calculate Digit Verification of CAS Registry Number 949595-91: (8*9)+(7*4)+(6*9)+(5*5)+(4*9)+(3*5)+(2*9)+(1*1)=249 249 % 10 = 9 So 949595-91-9 is a valid CAS Registry Number.