The CAS Registry Mumber 7310-92-1 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,3,1 and 0 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 7310-92: (6*7)+(5*3)+(4*1)+(3*0)+(2*9)+(1*2)=81 81 % 10 = 1 So 7310-92-1 is a valid CAS Registry Number.