USA Change in capex

[Devon Cash]

Hi!

New to the forum. I'm doing some prep for an IB interview. I'm confused as to why the depreciation expense from year 2 is added back to the net PP&E from year 2, but the depreciation expense from year 1 isn't added back to the net PP&E from year 1. More specifically, I'm uncertain about the logic behind the calculation 7,520 (net PP&E yr 2) + 781.4 (dep yr 2) - 6,434.5 (net PP&E yr 1) in determining the change in capex.

Thanks!