The CAS Registry Mumber 90919-48-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,0,9,1 and 9 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 90919-48: (7*9)+(6*0)+(5*9)+(4*1)+(3*9)+(2*4)+(1*8)=155 155 % 10 = 5 So 90919-48-5 is a valid CAS Registry Number.