The CAS Registry Mumber 743422-98-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,4,3,4,2 and 2 respectively; the second part has 2 digits, 9 and 8 respectively. Calculate Digit Verification of CAS Registry Number 743422-98: (8*7)+(7*4)+(6*3)+(5*4)+(4*2)+(3*2)+(2*9)+(1*8)=162 162 % 10 = 2 So 743422-98-2 is a valid CAS Registry Number.