The CAS Registry Mumber 143428-44-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,3,4,2 and 8 respectively; the second part has 2 digits, 4 and 4 respectively. Calculate Digit Verification of CAS Registry Number 143428-44: (8*1)+(7*4)+(6*3)+(5*4)+(4*2)+(3*8)+(2*4)+(1*4)=118 118 % 10 = 8 So 143428-44-8 is a valid CAS Registry Number.