The CAS Registry Mumber 84878-03-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,8,7 and 8 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 84878-03: (7*8)+(6*4)+(5*8)+(4*7)+(3*8)+(2*0)+(1*3)=175 175 % 10 = 5 So 84878-03-5 is a valid CAS Registry Number.