The CAS Registry Mumber 227605-22-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 2,2,7,6,0 and 5 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 227605-22: (8*2)+(7*2)+(6*7)+(5*6)+(4*0)+(3*5)+(2*2)+(1*2)=123 123 % 10 = 3 So 227605-22-3 is a valid CAS Registry Number.