The CAS Registry Mumber 55714-16-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,5,7,1 and 4 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 55714-16: (7*5)+(6*5)+(5*7)+(4*1)+(3*4)+(2*1)+(1*6)=124 124 % 10 = 4 So 55714-16-4 is a valid CAS Registry Number.