The CAS Registry Mumber 58434-75-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,4,3 and 4 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 58434-75: (7*5)+(6*8)+(5*4)+(4*3)+(3*4)+(2*7)+(1*5)=146 146 % 10 = 6 So 58434-75-6 is a valid CAS Registry Number.