The CAS Registry Mumber 132621-42-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,6,2 and 1 respectively; the second part has 2 digits, 4 and 2 respectively. Calculate Digit Verification of CAS Registry Number 132621-42: (8*1)+(7*3)+(6*2)+(5*6)+(4*2)+(3*1)+(2*4)+(1*2)=92 92 % 10 = 2 So 132621-42-2 is a valid CAS Registry Number.