The CAS Registry Mumber 77086-05-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,0,8 and 6 respectively; the second part has 2 digits, 0 and 5 respectively. Calculate Digit Verification of CAS Registry Number 77086-05: (7*7)+(6*7)+(5*0)+(4*8)+(3*6)+(2*0)+(1*5)=146 146 % 10 = 6 So 77086-05-6 is a valid CAS Registry Number.