The CAS Registry Mumber 59239-72-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,9,2,3 and 9 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 59239-72: (7*5)+(6*9)+(5*2)+(4*3)+(3*9)+(2*7)+(1*2)=154 154 % 10 = 4 So 59239-72-4 is a valid CAS Registry Number.