The CAS Registry Mumber 1695-07-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,6,9 and 5 respectively; the second part has 2 digits, 0 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1695-07: (6*1)+(5*6)+(4*9)+(3*5)+(2*0)+(1*7)=94 94 % 10 = 4 So 1695-07-4 is a valid CAS Registry Number.