The CAS Registry Mumber 4608-25-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,6,0 and 8 respectively; the second part has 2 digits, 2 and 5 respectively. Calculate Digit Verification of CAS Registry Number 4608-25: (6*4)+(5*6)+(4*0)+(3*8)+(2*2)+(1*5)=87 87 % 10 = 7 So 4608-25-7 is a valid CAS Registry Number.