The CAS Registry Mumber 134370-12-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,4,3,7 and 0 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 134370-12: (8*1)+(7*3)+(6*4)+(5*3)+(4*7)+(3*0)+(2*1)+(1*2)=100 100 % 10 = 0 So 134370-12-0 is a valid CAS Registry Number.