The CAS Registry Mumber 108234-26-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,8,2,3 and 4 respectively; the second part has 2 digits, 2 and 6 respectively. Calculate Digit Verification of CAS Registry Number 108234-26: (8*1)+(7*0)+(6*8)+(5*2)+(4*3)+(3*4)+(2*2)+(1*6)=100 100 % 10 = 0 So 108234-26-0 is a valid CAS Registry Number.