The CAS Registry Mumber 14415-31-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,4,4,1 and 5 respectively; the second part has 2 digits, 3 and 1 respectively. Calculate Digit Verification of CAS Registry Number 14415-31: (7*1)+(6*4)+(5*4)+(4*1)+(3*5)+(2*3)+(1*1)=77 77 % 10 = 7 So 14415-31-7 is a valid CAS Registry Number.