The CAS Registry Mumber 22024-99-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,2,0,2 and 4 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 22024-99: (7*2)+(6*2)+(5*0)+(4*2)+(3*4)+(2*9)+(1*9)=73 73 % 10 = 3 So 22024-99-3 is a valid CAS Registry Number.