The CAS Registry Mumber 83802-22-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,8,0 and 2 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 83802-22: (7*8)+(6*3)+(5*8)+(4*0)+(3*2)+(2*2)+(1*2)=126 126 % 10 = 6 So 83802-22-6 is a valid CAS Registry Number.