The CAS Registry Mumber 68605-06-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,6,0 and 5 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 68605-06: (7*6)+(6*8)+(5*6)+(4*0)+(3*5)+(2*0)+(1*6)=141 141 % 10 = 1 So 68605-06-1 is a valid CAS Registry Number.