The CAS Registry Mumber 53916-74-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,9,1 and 6 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 53916-74: (7*5)+(6*3)+(5*9)+(4*1)+(3*6)+(2*7)+(1*4)=138 138 % 10 = 8 So 53916-74-8 is a valid CAS Registry Number.