The CAS Registry Mumber 51385-48-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,1,3,8 and 5 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 51385-48: (7*5)+(6*1)+(5*3)+(4*8)+(3*5)+(2*4)+(1*8)=119 119 % 10 = 9 So 51385-48-9 is a valid CAS Registry Number.