The CAS Registry Mumber 4415-12-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,4,1 and 5 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 4415-12: (6*4)+(5*4)+(4*1)+(3*5)+(2*1)+(1*2)=67 67 % 10 = 7 So 4415-12-7 is a valid CAS Registry Number.