The CAS Registry Mumber 90045-93-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,0,4 and 5 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 90045-93: (7*9)+(6*0)+(5*0)+(4*4)+(3*5)+(2*9)+(1*3)=115 115 % 10 = 5 So 90045-93-5 is a valid CAS Registry Number.