The CAS Registry Mumber 174359-41-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,7,4,3,5 and 9 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 174359-41: (8*1)+(7*7)+(6*4)+(5*3)+(4*5)+(3*9)+(2*4)+(1*1)=152 152 % 10 = 2 So 174359-41-2 is a valid CAS Registry Number.