The CAS Registry Mumber 76143-40-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,1,4 and 3 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 76143-40: (7*7)+(6*6)+(5*1)+(4*4)+(3*3)+(2*4)+(1*0)=123 123 % 10 = 3 So 76143-40-3 is a valid CAS Registry Number.