The CAS Registry Mumber 68047-33-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,8,0,4 and 7 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 68047-33: (7*6)+(6*8)+(5*0)+(4*4)+(3*7)+(2*3)+(1*3)=136 136 % 10 = 6 So 68047-33-6 is a valid CAS Registry Number.