Value being subtracted to negatives

game.ReplicatedStorage.Events.Removed:FireServer(children.Strength.Value)

You could try and switch the variables around so it would be:

game.ReplicatedStorage.Events.Removed.OnServerEvent:Connect(function(player, Strength)
	player.Data.Damage.Value = Strength - player.Data.Damage.Value
end)

If this dosn’t work please show the script that is triggering the server event pls.

How is this being fired? Is it inside of a function? Is that function connected to an event? How many times is that event connected? Could be that FireServer is connected multiple times, or the Value you mean to send is not correct.

still did the same thing

It would really help if you could show the script that triggers the event. Like the script that is sending the strength value.