The CAS Registry Mumber 101038-24-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,1,0,3 and 8 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 101038-24: (8*1)+(7*0)+(6*1)+(5*0)+(4*3)+(3*8)+(2*2)+(1*4)=58 58 % 10 = 8 So 101038-24-8 is a valid CAS Registry Number.