Those calculations are for oxygen required to breathe, not carbon dioxide exhaled by people. The cycle for biologically produced and consumed CO2 tends to be carbon neutral.

As far as I'm aware, the issue isn't with CO2 produced by cellular respiration, the issue is the burning of fuels dug up from the ground and the destruction of natural carbon sinks.

That's ok, I've planted 920,000.

It's not how many you've planted, it's how many are still alive at age 20.

They all had good quality and trees make pine cones.

The maths may be right but the thought is wrong since it takes zero trees to offset the whole world's population of air-breathing organisms as all the CO₂ they produce started out as... CO₂. This is taken up by algae and plants, which are eaten by organisms which are eaten themselves until the target organism is reached, which will use the energy gained from consuming the previous hop in the carbon chain, breathing out CO₂ upon which the circle is complete.

Had humans consumed fossilised carbon the thought would still be wrong since trees only store the carbon temporarily, eventually it is released as CO₂ when the tree burns up or rots away.

This leaves aside the whole discussion on whether there is any need to offset CO₂ from non-fossil sources - which there is not as far as I can see.