The CAS Registry Mumber 92229-20-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,2,2,2 and 9 respectively; the second part has 2 digits, 2 and 0 respectively. Calculate Digit Verification of CAS Registry Number 92229-20: (7*9)+(6*2)+(5*2)+(4*2)+(3*9)+(2*2)+(1*0)=124 124 % 10 = 4 So 92229-20-4 is a valid CAS Registry Number.