How do I calculate the Adjustment row on the Statement of Income and Retained Earnings?

The management of Pina Instrument Company had concluded, with the concurrence of its independent auditors, that results of operations would be more fairly presented if Pina changed its method of pricing inventory from last-in, rst-out (LIFO) to average-cost in 2020. Given below is the 5-year summary of income under LIFO and a schedule of what the inventories would be if stated on the averagecost method. PINA INSTRUMENT COMPANY STATEMENT OF INCOME AND RETAINED EARNINGS FOR THE YEARS ENDED MAY 31 2016 2017 2018 2019 2020 Salesnet $13,820 $15,490 $16,640 $18,380 $19,050 Cost of goods sold Beginning inventory 1,010 1,090 1,010 1,100 1,230 Purchases 13,010 13,830 15,150 15,820 15,519 Ending inventory (1,090) (1,010) (1,100) (1,230) (1,380) Total 12,930 13,910 15,060 15,690 15,369 Gross prot 890 1,580 1,580 2,690 3,681 Administrative expenses 700 760 830 910 990 Income before taxes 190 820 750 1,780 2,691 Income taxes (50%) 95 410 375 890 1,346 Net income 95 410 375 890 1,345 Retained earningsbeginning 1,220 1,315 1,725 2,100 2,990 Retained earningsending $1,315 $1,725 $2,100 $2,990 $4,335 Earnings per share $0.95 $4.10 $3.75 $8.90 $13.45 SCHEDULE OF INVENTORY BALANCES USING AVERAGE-COST METHOD FOR THE YEARS ENDED MAY 31 2015 2016 2017 2018 2019 2020 $1,020 $1,110 $1,130 $1,260 $1,500 $1,720