The CAS Registry Mumber 54548-46-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,4,5,4 and 8 respectively; the second part has 2 digits, 4 and 6 respectively. Calculate Digit Verification of CAS Registry Number 54548-46: (7*5)+(6*4)+(5*5)+(4*4)+(3*8)+(2*4)+(1*6)=138 138 % 10 = 8 So 54548-46-8 is a valid CAS Registry Number.