The CAS Registry Mumber 131942-08-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,1,9,4 and 2 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 131942-08: (8*1)+(7*3)+(6*1)+(5*9)+(4*4)+(3*2)+(2*0)+(1*8)=110 110 % 10 = 0 So 131942-08-0 is a valid CAS Registry Number.