The CAS Registry Mumber 104516-48-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,5,1 and 6 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 104516-48: (8*1)+(7*0)+(6*4)+(5*5)+(4*1)+(3*6)+(2*4)+(1*8)=95 95 % 10 = 5 So 104516-48-5 is a valid CAS Registry Number.