The CAS Registry Mumber 88434-48-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,8,4,3 and 4 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 88434-48: (7*8)+(6*8)+(5*4)+(4*3)+(3*4)+(2*4)+(1*8)=164 164 % 10 = 4 So 88434-48-4 is a valid CAS Registry Number.