The CAS Registry Mumber 83654-48-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,6,5 and 4 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 83654-48: (7*8)+(6*3)+(5*6)+(4*5)+(3*4)+(2*4)+(1*8)=152 152 % 10 = 2 So 83654-48-2 is a valid CAS Registry Number.