The CAS Registry Mumber 90957-11-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,9,5 and 7 respectively; the second part has 2 digits, 1 and 1 respectively. Calculate Digit Verification of CAS Registry Number 90957-11: (7*9)+(6*0)+(5*9)+(4*5)+(3*7)+(2*1)+(1*1)=152 152 % 10 = 2 So 90957-11-2 is a valid CAS Registry Number.