The CAS Registry Mumber 40224-39-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,0,2,2 and 4 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 40224-39: (7*4)+(6*0)+(5*2)+(4*2)+(3*4)+(2*3)+(1*9)=73 73 % 10 = 3 So 40224-39-3 is a valid CAS Registry Number.