The CAS Registry Mumber 82639-48-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,2,6,3 and 9 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 82639-48: (7*8)+(6*2)+(5*6)+(4*3)+(3*9)+(2*4)+(1*8)=153 153 % 10 = 3 So 82639-48-3 is a valid CAS Registry Number.