The CAS Registry Mumber 79798-06-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,7,9 and 8 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 79798-06: (7*7)+(6*9)+(5*7)+(4*9)+(3*8)+(2*0)+(1*6)=204 204 % 10 = 4 So 79798-06-4 is a valid CAS Registry Number.