The CAS Registry Mumber 99948-64-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,9,9,4 and 8 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 99948-64: (7*9)+(6*9)+(5*9)+(4*4)+(3*8)+(2*6)+(1*4)=218 218 % 10 = 8 So 99948-64-8 is a valid CAS Registry Number.