formula for plus and minus figures

Is there any formula or way by which I can put numbers in plus and minus both in a certain range (it does not matter whatever the length of numbers), as an example i'm attaching a sheet but for this I have to put minus sign before the formula and have to choose different cells at random

So do you want random numbers between -500 & -1000 OR +500 & +1000?

yes but both the numbers in the range it does not matter the length and range for numbers, it may two cell or thousand cells

What about this;

Formula:

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Thank you very much for your solution