The CAS Registry Mumber 89964-48-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,9,6 and 4 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 89964-48: (7*8)+(6*9)+(5*9)+(4*6)+(3*4)+(2*4)+(1*8)=207 207 % 10 = 7 So 89964-48-7 is a valid CAS Registry Number.