The CAS Registry Mumber 91294-52-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,1,2,9 and 4 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 91294-52: (7*9)+(6*1)+(5*2)+(4*9)+(3*4)+(2*5)+(1*2)=139 139 % 10 = 9 So 91294-52-9 is a valid CAS Registry Number.