The CAS Registry Mumber 134258-27-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,2,5 and 8 respectively; the second part has 2 digits, 2 and 7 respectively. Calculate Digit Verification of CAS Registry Number 134258-27: (8*1)+(7*3)+(6*4)+(5*2)+(4*5)+(3*8)+(2*2)+(1*7)=118 118 % 10 = 8 So 134258-27-8 is a valid CAS Registry Number.