The CAS Registry Mumber 134241-04-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,2,4 and 1 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 134241-04: (8*1)+(7*3)+(6*4)+(5*2)+(4*4)+(3*1)+(2*0)+(1*4)=86 86 % 10 = 6 So 134241-04-6 is a valid CAS Registry Number.