The CAS Registry Mumber 2084-24-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,0,8 and 4 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 2084-24: (6*2)+(5*0)+(4*8)+(3*4)+(2*2)+(1*4)=64 64 % 10 = 4 So 2084-24-4 is a valid CAS Registry Number.