The CAS Registry Mumber 24800-34-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,4,8,0 and 0 respectively; the second part has 2 digits, 3 and 4 respectively. Calculate Digit Verification of CAS Registry Number 24800-34: (7*2)+(6*4)+(5*8)+(4*0)+(3*0)+(2*3)+(1*4)=88 88 % 10 = 8 So 24800-34-8 is a valid CAS Registry Number.