The CAS Registry Mumber 84942-49-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,9,4 and 2 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 84942-49: (7*8)+(6*4)+(5*9)+(4*4)+(3*2)+(2*4)+(1*9)=164 164 % 10 = 4 So 84942-49-4 is a valid CAS Registry Number.