The CAS Registry Mumber 86194-42-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,1,9 and 4 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 86194-42: (7*8)+(6*6)+(5*1)+(4*9)+(3*4)+(2*4)+(1*2)=155 155 % 10 = 5 So 86194-42-5 is a valid CAS Registry Number.