The CAS Registry Mumber 79054-67-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,0,5 and 4 respectively; the second part has 2 digits, 6 and 7 respectively. Calculate Digit Verification of CAS Registry Number 79054-67: (7*7)+(6*9)+(5*0)+(4*5)+(3*4)+(2*6)+(1*7)=154 154 % 10 = 4 So 79054-67-4 is a valid CAS Registry Number.