The CAS Registry Mumber 84012-12-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,0,1 and 2 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 84012-12: (7*8)+(6*4)+(5*0)+(4*1)+(3*2)+(2*1)+(1*2)=94 94 % 10 = 4 So 84012-12-4 is a valid CAS Registry Number.