The CAS Registry Mumber 143167-26-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,3,1,6 and 7 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 143167-26: (8*1)+(7*4)+(6*3)+(5*1)+(4*6)+(3*7)+(2*2)+(1*6)=114 114 % 10 = 4 So 143167-26-4 is a valid CAS Registry Number.