The CAS Registry Mumber 11350-53-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,1,3,5 and 0 respectively; the second part has 2 digits, 5 and 3 respectively. Calculate Digit Verification of CAS Registry Number 11350-53: (7*1)+(6*1)+(5*3)+(4*5)+(3*0)+(2*5)+(1*3)=61 61 % 10 = 1 So 11350-53-1 is a valid CAS Registry Number.