The CAS Registry Mumber 115374-93-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,5,3,7 and 4 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 115374-93: (8*1)+(7*1)+(6*5)+(5*3)+(4*7)+(3*4)+(2*9)+(1*3)=121 121 % 10 = 1 So 115374-93-1 is a valid CAS Registry Number.