The CAS Registry Mumber 119722-21-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,9,7,2 and 2 respectively; the second part has 2 digits, 2 and 1 respectively. Calculate Digit Verification of CAS Registry Number 119722-21: (8*1)+(7*1)+(6*9)+(5*7)+(4*2)+(3*2)+(2*2)+(1*1)=123 123 % 10 = 3 So 119722-21-3 is a valid CAS Registry Number.