Start with the income statement rather than the listing description. Gross rent minus a realistic vacancy allowance, property taxes, insurance, utilities not covered by tenants and ongoing maintenance produces the net operating income a lender or investor will actually underwrite against, and that number is frequently smaller than a seller's advertised gross rent suggests.
Then confirm legality, because income a City file does not support is income a lender will not count. Only a permitted unit under the City of Saskatoon's rules produces rent an appraiser can credit, and the Residential Tenancies Act, 2006 governs how existing leases transfer to a new owner.
Comparable sold income properties round out the picture by showing what similar cash flows have actually traded for recently, which corrects for a market that may value income differently than a pure math exercise would suggest. Get your hand-reviewed valuation from Joel Dyck.