The CAS Registry Mumber 25426-48-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,5,4,2 and 6 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 25426-48: (7*2)+(6*5)+(5*4)+(4*2)+(3*6)+(2*4)+(1*8)=106 106 % 10 = 6 So 25426-48-6 is a valid CAS Registry Number.