Determine taxable income in each of the following independent cases. In all cases, the company was very profitable in all years prior to 2017 and it had retained earnings of $1,000,000 at the end of 2017.

1. In 2018, Company A has taxable income of $60,000 prior to consideration of any net operating loss. In 2017, the Company incurred a net operating loss of $10,000. They did not elect to waive the carryback period. Determine 2018 taxable income.

2. In 2018, Company B has taxable income of $50,000 prior to consideration of any net operating loss. In 2017, the Company incurred a net operating loss of $20,000. They elected to waive the carryback period. Determine 2018 taxable income.

3. In 2019, Company C has taxable income of $35,000 prior to consideration of any net operating loss. In 2018, the Company incurred a net operating loss of $30,000. Determine 2019 taxable income.

4. In 2019, Company D has taxable income of $35,000 prior to consideration of any net operating loss. In 2017, the Company incurred a net operating loss of $5,000. They elected to waive the carryback period. In 2018, the Company incurred a net operating loss of $40,000. Determine 2019 taxable income.