The CAS Registry Mumber 132356-41-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,3,5 and 6 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 132356-41: (8*1)+(7*3)+(6*2)+(5*3)+(4*5)+(3*6)+(2*4)+(1*1)=103 103 % 10 = 3 So 132356-41-3 is a valid CAS Registry Number.