The CAS Registry Mumber 34238-52-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,4,2,3 and 8 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 34238-52: (7*3)+(6*4)+(5*2)+(4*3)+(3*8)+(2*5)+(1*2)=103 103 % 10 = 3 So 34238-52-3 is a valid CAS Registry Number.