The CAS Registry Mumber 79108-54-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,1,0 and 8 respectively; the second part has 2 digits, 5 and 4 respectively. Calculate Digit Verification of CAS Registry Number 79108-54: (7*7)+(6*9)+(5*1)+(4*0)+(3*8)+(2*5)+(1*4)=146 146 % 10 = 6 So 79108-54-6 is a valid CAS Registry Number.