The CAS Registry Mumber 57001-16-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,0,0 and 1 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 57001-16: (7*5)+(6*7)+(5*0)+(4*0)+(3*1)+(2*1)+(1*6)=88 88 % 10 = 8 So 57001-16-8 is a valid CAS Registry Number.