The CAS Registry Mumber 83792-90-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,7,9 and 2 respectively; the second part has 2 digits, 9 and 0 respectively. Calculate Digit Verification of CAS Registry Number 83792-90: (7*8)+(6*3)+(5*7)+(4*9)+(3*2)+(2*9)+(1*0)=169 169 % 10 = 9 So 83792-90-9 is a valid CAS Registry Number.