The CAS Registry Mumber 891488-65-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,9,1,4,8 and 8 respectively; the second part has 2 digits, 6 and 5 respectively. Calculate Digit Verification of CAS Registry Number 891488-65: (8*8)+(7*9)+(6*1)+(5*4)+(4*8)+(3*8)+(2*6)+(1*5)=226 226 % 10 = 6 So 891488-65-6 is a valid CAS Registry Number.