The CAS Registry Mumber 84855-92-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,8,5 and 5 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 84855-92: (7*8)+(6*4)+(5*8)+(4*5)+(3*5)+(2*9)+(1*2)=175 175 % 10 = 5 So 84855-92-5 is a valid CAS Registry Number.