The CAS Registry Mumber 77169-06-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,1,6 and 9 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 77169-06: (7*7)+(6*7)+(5*1)+(4*6)+(3*9)+(2*0)+(1*6)=153 153 % 10 = 3 So 77169-06-3 is a valid CAS Registry Number.