The CAS Registry Mumber 83611-02-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,6,1 and 1 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 83611-02: (7*8)+(6*3)+(5*6)+(4*1)+(3*1)+(2*0)+(1*2)=113 113 % 10 = 3 So 83611-02-3 is a valid CAS Registry Number.