The CAS Registry Mumber 73674-25-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,3,6,7 and 4 respectively; the second part has 2 digits, 2 and 5 respectively. Calculate Digit Verification of CAS Registry Number 73674-25: (7*7)+(6*3)+(5*6)+(4*7)+(3*4)+(2*2)+(1*5)=146 146 % 10 = 6 So 73674-25-6 is a valid CAS Registry Number.