The CAS Registry Mumber 1867-85-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,8,6 and 7 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 1867-85: (6*1)+(5*8)+(4*6)+(3*7)+(2*8)+(1*5)=112 112 % 10 = 2 So 1867-85-2 is a valid CAS Registry Number.