The CAS Registry Mumber 24430-01-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,4,4,3 and 0 respectively; the second part has 2 digits, 0 and 1 respectively. Calculate Digit Verification of CAS Registry Number 24430-01: (7*2)+(6*4)+(5*4)+(4*3)+(3*0)+(2*0)+(1*1)=71 71 % 10 = 1 So 24430-01-1 is a valid CAS Registry Number.