Greer Incorporated discovered the following errors on the books at the beginning of 2021:

a. Maintenance expense on account was overstated by $20,000 in 2019 and understated by $30,000 in 2020. The payables for both years are still unpaid.

b. Depreciation expense was overstated by $55,000 in 2019 and understated by $70,000 in 2020.

c. Ending inventory was understated by $120,000 in 2019 and overstated by $178,000 in 2020.

Required 

Prepare the entry required to correct these entries in 2021 when they are discovered, assuming that books have been closed for both 2019 and 2020. Greer does not prepare comparative statements.