The CAS Registry Mumber 105494-88-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,5,4,9 and 4 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 105494-88: (8*1)+(7*0)+(6*5)+(5*4)+(4*9)+(3*4)+(2*8)+(1*8)=130 130 % 10 = 0 So 105494-88-0 is a valid CAS Registry Number.