The CAS Registry Mumber 13342-88-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,3,4 and 2 respectively; the second part has 2 digits, 8 and 8 respectively. Calculate Digit Verification of CAS Registry Number 13342-88: (7*1)+(6*3)+(5*3)+(4*4)+(3*2)+(2*8)+(1*8)=86 86 % 10 = 6 So 13342-88-6 is a valid CAS Registry Number.