The CAS Registry Mumber 80822-31-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,8,2 and 2 respectively; the second part has 2 digits, 3 and 1 respectively. Calculate Digit Verification of CAS Registry Number 80822-31: (7*8)+(6*0)+(5*8)+(4*2)+(3*2)+(2*3)+(1*1)=117 117 % 10 = 7 So 80822-31-7 is a valid CAS Registry Number.