The CAS Registry Mumber 75319-59-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,3,1 and 9 respectively; the second part has 2 digits, 5 and 9 respectively. Calculate Digit Verification of CAS Registry Number 75319-59: (7*7)+(6*5)+(5*3)+(4*1)+(3*9)+(2*5)+(1*9)=144 144 % 10 = 4 So 75319-59-4 is a valid CAS Registry Number.