The CAS Registry Mumber 78889-48-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,8,8,8 and 9 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 78889-48: (7*7)+(6*8)+(5*8)+(4*8)+(3*9)+(2*4)+(1*8)=212 212 % 10 = 2 So 78889-48-2 is a valid CAS Registry Number.