The CAS Registry Mumber 1892-33-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,8,9 and 2 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 1892-33: (6*1)+(5*8)+(4*9)+(3*2)+(2*3)+(1*3)=97 97 % 10 = 7 So 1892-33-7 is a valid CAS Registry Number.