The CAS Registry Mumber 107263-08-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,7,2,6 and 3 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 107263-08: (8*1)+(7*0)+(6*7)+(5*2)+(4*6)+(3*3)+(2*0)+(1*8)=101 101 % 10 = 1 So 107263-08-1 is a valid CAS Registry Number.