The CAS Registry Mumber 143982-53-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,3,9,8 and 2 respectively; the second part has 2 digits, 5 and 3 respectively. Calculate Digit Verification of CAS Registry Number 143982-53: (8*1)+(7*4)+(6*3)+(5*9)+(4*8)+(3*2)+(2*5)+(1*3)=150 150 % 10 = 0 So 143982-53-0 is a valid CAS Registry Number.