The CAS Registry Mumber 5824-87-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,8,2 and 4 respectively; the second part has 2 digits, 8 and 7 respectively. Calculate Digit Verification of CAS Registry Number 5824-87: (6*5)+(5*8)+(4*2)+(3*4)+(2*8)+(1*7)=113 113 % 10 = 3 So 5824-87-3 is a valid CAS Registry Number.