The CAS Registry Mumber 68916-47-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,9,1 and 6 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 68916-47: (7*6)+(6*8)+(5*9)+(4*1)+(3*6)+(2*4)+(1*7)=172 172 % 10 = 2 So 68916-47-2 is a valid CAS Registry Number.