The CAS Registry Mumber 77486-43-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,4,8 and 6 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 77486-43: (7*7)+(6*7)+(5*4)+(4*8)+(3*6)+(2*4)+(1*3)=172 172 % 10 = 2 So 77486-43-2 is a valid CAS Registry Number.