On April 1, 20X1, Sigma Corporation acquired a patent for $60,000 cash. The patent has a useful life of 10 years. Calculate the amortization expense for the year 20X1 using the straight-line method.

Additionally, Sigma Corporation made the following transactions during 20X1:

• June 1: Paid $4,000 for patent maintenance fees.
• September 1: Sold the patent for $50,000 cash.

Required:

• Calculate the total amortization expense for the year 20X1.
• Prepare journal entries for the patent-related transactions.