The CAS Registry Mumber 362603-58-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,6,2,6,0 and 3 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 362603-58: (8*3)+(7*6)+(6*2)+(5*6)+(4*0)+(3*3)+(2*5)+(1*8)=135 135 % 10 = 5 So 362603-58-5 is a valid CAS Registry Number.