The CAS Registry Mumber 88791-37-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,8,7,9 and 1 respectively; the second part has 2 digits, 3 and 7 respectively. Calculate Digit Verification of CAS Registry Number 88791-37: (7*8)+(6*8)+(5*7)+(4*9)+(3*1)+(2*3)+(1*7)=191 191 % 10 = 1 So 88791-37-1 is a valid CAS Registry Number.