The CAS Registry Mumber 51110-45-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,1,1,1 and 0 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 51110-45: (7*5)+(6*1)+(5*1)+(4*1)+(3*0)+(2*4)+(1*5)=63 63 % 10 = 3 So 51110-45-3 is a valid CAS Registry Number.