The CAS Registry Mumber 2065-48-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,0,6 and 5 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 2065-48: (6*2)+(5*0)+(4*6)+(3*5)+(2*4)+(1*8)=67 67 % 10 = 7 So 2065-48-7 is a valid CAS Registry Number.