The CAS Registry Mumber 83792-98-7 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 8 respectively. Calculate Digit Verification of CAS Registry Number 83792-98: (7*8)+(6*3)+(5*7)+(4*9)+(3*2)+(2*9)+(1*8)=177 177 % 10 = 7 So 83792-98-7 is a valid CAS Registry Number.