The CAS Registry Mumber 1994-52-1 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,9,9 and 4 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 1994-52: (6*1)+(5*9)+(4*9)+(3*4)+(2*5)+(1*2)=111 111 % 10 = 1 So 1994-52-1 is a valid CAS Registry Number.