The CAS Registry Mumber 79054-66-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,0,5 and 4 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 79054-66: (7*7)+(6*9)+(5*0)+(4*5)+(3*4)+(2*6)+(1*6)=153 153 % 10 = 3 So 79054-66-3 is a valid CAS Registry Number.