The CAS Registry Mumber 84012-19-1 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 9 respectively. Calculate Digit Verification of CAS Registry Number 84012-19: (7*8)+(6*4)+(5*0)+(4*1)+(3*2)+(2*1)+(1*9)=101 101 % 10 = 1 So 84012-19-1 is a valid CAS Registry Number.