The CAS Registry Mumber 1099616-49-5 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,0,9,9,6,1 and 6 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1099616-49: (9*1)+(8*0)+(7*9)+(6*9)+(5*6)+(4*1)+(3*6)+(2*4)+(1*9)=195 195 % 10 = 5 So 1099616-49-5 is a valid CAS Registry Number.