The CAS Registry Mumber 37231-92-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,7,2,3 and 1 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 37231-92: (7*3)+(6*7)+(5*2)+(4*3)+(3*1)+(2*9)+(1*2)=108 108 % 10 = 8 So 37231-92-8 is a valid CAS Registry Number.