The CAS Registry Mumber 141345-57-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,1,3,4 and 5 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 141345-57: (8*1)+(7*4)+(6*1)+(5*3)+(4*4)+(3*5)+(2*5)+(1*7)=105 105 % 10 = 5 So 141345-57-5 is a valid CAS Registry Number.