To update your checks to have this information:

1. In Accounts Payable or Payroll > Banks > click Edit Account Details
2. Select the Payments tab > Highlight computer checks 
3. Select one of the default blank paper formats and click Edit payment options at the bottom 
4. In the first check format section at the top - enter the fractional routing number into the field for "Transit ABA number" - for example 1-3/310
5. Click OK
6. Save and close the bank