The CAS Registry Mumber 1302-58-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,3,0 and 2 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 1302-58: (6*1)+(5*3)+(4*0)+(3*2)+(2*5)+(1*8)=45 45 % 10 = 5 So 1302-58-5 is a valid CAS Registry Number.