The CAS Registry Mumber 26293-58-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,6,2,9 and 3 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 26293-58: (7*2)+(6*6)+(5*2)+(4*9)+(3*3)+(2*5)+(1*8)=123 123 % 10 = 3 So 26293-58-3 is a valid CAS Registry Number.