The CAS Registry Mumber 22033-64-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,2,0,3 and 3 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 22033-64: (7*2)+(6*2)+(5*0)+(4*3)+(3*3)+(2*6)+(1*4)=63 63 % 10 = 3 So 22033-64-3 is a valid CAS Registry Number.