The CAS Registry Mumber 111896-72-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,1,8,9 and 6 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 111896-72: (8*1)+(7*1)+(6*1)+(5*8)+(4*9)+(3*6)+(2*7)+(1*2)=131 131 % 10 = 1 So 111896-72-1 is a valid CAS Registry Number.