The CAS Registry Mumber 82207-12-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,2,0 and 7 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 82207-12: (7*8)+(6*2)+(5*2)+(4*0)+(3*7)+(2*1)+(1*2)=103 103 % 10 = 3 So 82207-12-3 is a valid CAS Registry Number.