The CAS Registry Mumber 103348-71-6 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, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 103348-71: (8*1)+(7*0)+(6*3)+(5*3)+(4*4)+(3*8)+(2*7)+(1*1)=96 96 % 10 = 6 So 103348-71-6 is a valid CAS Registry Number.