What does tangible net worth means?

Net worth means the cost (amount paid at the purchase date plus any capitalized costs like major improvements) offset by the accumulated depreciation/amortization.

For example, you purchase a building for $1m and made a major improvements of 500k. The cost of the tangible asset is on the balance sheet for 1.5m. Then as time goes by you will depreciate the building based on its expected life. Let's say the building has a ten year life then you will depreciate 150k every year.

Two years from the purchase/improvement date, you have the cost of $1.5m and the accumulated depreciation of $300k. the net worth of the building is $1.2m