The CAS Registry Mumber 75906-43-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,9,0 and 6 respectively; the second part has 2 digits, 4 and 3 respectively. Calculate Digit Verification of CAS Registry Number 75906-43: (7*7)+(6*5)+(5*9)+(4*0)+(3*6)+(2*4)+(1*3)=153 153 % 10 = 3 So 75906-43-3 is a valid CAS Registry Number.