The CAS Registry Mumber 99268-44-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,9,2,6 and 8 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 99268-44: (7*9)+(6*9)+(5*2)+(4*6)+(3*8)+(2*4)+(1*4)=187 187 % 10 = 7 So 99268-44-7 is a valid CAS Registry Number.