Net worth = total assets - total liabilities
Your net worth is all of the non-financial and financial assets that a person or unit own minus all of the outstanding liabilities.
An asset is anything of value and a liability is all debt owed.
Total assets
325,000 (house) + 750 (guitar) + 15,000 (car) + 8,000 (investments) + 2,100 (savings)
=350,850
Total liabilities
245,000 (mortgage) + 9,000 (car loans)
=254,000
Net worth
350,850 − 254,000
=96,850