The CAS Registry Mumber 104435-58-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,4,3 and 5 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 104435-58: (8*1)+(7*0)+(6*4)+(5*4)+(4*3)+(3*5)+(2*5)+(1*8)=97 97 % 10 = 7 So 104435-58-7 is a valid CAS Registry Number.