The CAS Registry Mumber 854268-72-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,5,4,2,6 and 8 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 854268-72: (8*8)+(7*5)+(6*4)+(5*2)+(4*6)+(3*8)+(2*7)+(1*2)=197 197 % 10 = 7 So 854268-72-7 is a valid CAS Registry Number.