Simple Derma Button Math Help

[JaceQuads]

Hi, first post here, i'm pretty new at learning lua and I cannot figure out why this derma button won't preform some basic math, any help would be appreciated!
local function CalcMenu()
local numnum = 1
local CalcFrame = vgui.Create( "DFrame" )
CalcFrame:SetPos( ScrW() / 2, ScrH() / 2 )
CalcFrame:SetSize( ScrW() / 3, ScrH() / 1.25 )
CalcFrame:ShowCloseButton( false )
CalcFrame:SetDraggable( false )
CalcFrame:ShowCloseButton( false )
CalcFrame:SetVisible( true )
CalcFrame:MakePopup()
CalcFrame:Center()

local TheButton = vgui.Create( "DButton", CalcFrame )
TheButton:SetText( "Boop" )
TheButton:SetSize( 1, 1 )
TheButton:Dock( FILL )
TheButton.DoClick = function()
if numnum <= 1 then
numnum = 9
else
numnum -= 1
end
print(numfac)
end
end

[Ljgoombruh]

This isn't valid in Lua; use var = var - 1 instead. Same goes for +=, -- and ++.
Make sure you post any errors that you get in the future.

[JaceQuads]

Cool! Ill try it out!