The CAS Registry Mumber 103348-68-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,3,4 and 8 respectively; the second part has 2 digits, 6 and 8 respectively. Calculate Digit Verification of CAS Registry Number 103348-68: (8*1)+(7*0)+(6*3)+(5*3)+(4*4)+(3*8)+(2*6)+(1*8)=101 101 % 10 = 1 So 103348-68-1 is a valid CAS Registry Number.