(100/10) x3 = 300,000 yuan.
The price is 800,000 yuan and the business tax rate is 5%. (Other taxes and fees are not considered)
Debit: Bank deposit 80
Cumulative amortization-patent right 30
Loan: non-operating income-income from disposal of non-current assets 6
Intangible assets-patent 100
Taxes payable-business tax payable 4
Then the profit and loss that affects the current period when the patent is sold is (60,000 yuan).
Personal opinion, for reference only.