The CAS Registry Mumber 77406-48-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,4,0 and 6 respectively; the second part has 2 digits, 4 and 8 respectively. Calculate Digit Verification of CAS Registry Number 77406-48: (7*7)+(6*7)+(5*4)+(4*0)+(3*6)+(2*4)+(1*8)=145 145 % 10 = 5 So 77406-48-5 is a valid CAS Registry Number.