The CAS Registry Mumber 135145-30-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,5,1,4 and 5 respectively; the second part has 2 digits, 3 and 0 respectively. Calculate Digit Verification of CAS Registry Number 135145-30: (8*1)+(7*3)+(6*5)+(5*1)+(4*4)+(3*5)+(2*3)+(1*0)=101 101 % 10 = 1 So 135145-30-1 is a valid CAS Registry Number.