The CAS Registry Mumber 5925-33-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,9,2 and 5 respectively; the second part has 2 digits, 3 and 3 respectively. Calculate Digit Verification of CAS Registry Number 5925-33: (6*5)+(5*9)+(4*2)+(3*5)+(2*3)+(1*3)=107 107 % 10 = 7 So 5925-33-7 is a valid CAS Registry Number.