The CAS Registry Mumber 186709-08-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,8,6,7,0 and 9 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 186709-08: (8*1)+(7*8)+(6*6)+(5*7)+(4*0)+(3*9)+(2*0)+(1*8)=170 170 % 10 = 0 So 186709-08-0 is a valid CAS Registry Number.