The CAS Registry Mumber 153076-23-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,3,0,7 and 6 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 153076-23: (8*1)+(7*5)+(6*3)+(5*0)+(4*7)+(3*6)+(2*2)+(1*3)=114 114 % 10 = 4 So 153076-23-4 is a valid CAS Registry Number.