The CAS Registry Mumber 57093-98-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,0,9 and 3 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 57093-98: (7*5)+(6*7)+(5*0)+(4*9)+(3*3)+(2*9)+(1*8)=148 148 % 10 = 8 So 57093-98-8 is a valid CAS Registry Number.