The CAS Registry Mumber 79512-31-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,9,5,1 and 2 respectively; the second part has 2 digits, 3 and 1 respectively. Calculate Digit Verification of CAS Registry Number 79512-31: (7*7)+(6*9)+(5*5)+(4*1)+(3*2)+(2*3)+(1*1)=145 145 % 10 = 5 So 79512-31-5 is a valid CAS Registry Number.