I have a strange error concerning this script, even though the script runs fine?

I cannot tell if this script works or not, because it does seem to make my game lag less, but it has an error at the comma in line 4 (in the 40,000). Can someone help with this issue I have, and if the script is fine the way it is. Just comment, thank you. (By the way, to see the the comma underlined with red, you have to create a script and insert the code into it.)

mx = game.Debris
mx2 = game.Debris.MaxItems

if (mx.MaxItems > 40,000) then
	mx.MaxItems = mx2*.75
end