The CAS Registry Mumber 43140-84-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,3,1,4 and 0 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 43140-84: (7*4)+(6*3)+(5*1)+(4*4)+(3*0)+(2*8)+(1*4)=87 87 % 10 = 7 So 43140-84-7 is a valid CAS Registry Number.