Hi , I am trying to understand mathematically how things work on trading with indices mainly dowj and FTSE 100.

So I will take the DOWJ as an example

Market open at 20000

I have £100 pound in my account. I choose a leverage of 1:500.

I buy one lot , so will require (20000/500) which is £40pounds.

Market close at 18000. So I have made a loss.

Questions

- how do I calculate the loss

2)similarly if market close at 22000, how do I calculate profit - how do I calculate minimum amount of money I need to keep my position open
- how long can I keep that position open
- silly question , how do I close a position on trading 212 if I am trading on the DOWJ for example. Can’t find close button .

I trialled with 24 option and the supposedly account manager could not answer these simple question. So planning to change to 212.

Many thanks

Cheers