The CAS Registry Mumber 9013-75-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 9,0,1 and 3 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 9013-75: (6*9)+(5*0)+(4*1)+(3*3)+(2*7)+(1*5)=86 86 % 10 = 6 So 9013-75-6 is a valid CAS Registry Number.