The CAS Registry Mumber 119336-23-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,9,3,3 and 6 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 119336-23: (8*1)+(7*1)+(6*9)+(5*3)+(4*3)+(3*6)+(2*2)+(1*3)=121 121 % 10 = 1 So 119336-23-1 is a valid CAS Registry Number.