The CAS Registry Mumber 147155-45-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,7,1,5 and 5 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 147155-45: (8*1)+(7*4)+(6*7)+(5*1)+(4*5)+(3*5)+(2*4)+(1*5)=131 131 % 10 = 1 So 147155-45-1 is a valid CAS Registry Number.