The CAS Registry Mumber 890122-43-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,9,0,1,2 and 2 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 890122-43: (8*8)+(7*9)+(6*0)+(5*1)+(4*2)+(3*2)+(2*4)+(1*3)=157 157 % 10 = 7 So 890122-43-7 is a valid CAS Registry Number.