The CAS Registry Mumber 7592-26-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,5,9 and 2 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 7592-26: (6*7)+(5*5)+(4*9)+(3*2)+(2*2)+(1*6)=119 119 % 10 = 9 So 7592-26-9 is a valid CAS Registry Number.