Praxis 2 - the indenting sequel

display.setStatusBar(display.HiddenStatusBar);

-- Prototypes
local MathSetup, ScreenSetup, NumPush, CalcIt, Reset

-- Variables
local _H = display.contentHeight;
local _W = display.contentWidth;
local CurrentInput
local result, ChosenOperator
local group

--Setup Math - Randomize Variables
function MathSetup(a,b,c)

    -- Create fresh group for the problem to be displayed in
    group            = display.newGroup()
    group.x, group.y = 0, 0

    -- Resets the input
    CurrentInput = 0

    --Randomizing Problem
    local a = math.random(1,9)
    local b = math.random(1,9)

    -- Finding Out What Problem Is And Associating Its Integers And Symbol With Images
    local NumImg1 = "assets/images/numbers/" .. tostring( NumA ) .. ".png"
    local NumImg2 = "assets/images/numbers/" .. tostring( NumB ) .. ".png"

    local Operator
    local operations = { "+", "-", "/", "*" }
    ChosenOperation  = operations[ math.random( 4 ) ]
    if ChosenOperator == "+" then
        Operator = "assets/images/add.png"
        result   = a + b
    elseif ChosenOperator == "-" then
        Operator = "assets/images/subtract.png"
        result   = a - b
    elseif ChosenOperator == "*" then
        Operator = "assets/images/multiply.png"
        result   = a * b
    elseif ChosenOperator == "/" then
        Operator = "assets/images/divide.png"
        result   = a / b
    end

    --Displaying The Problem's Images
    local myImage = display.newImageRect((NumImg1), 100 ,100)
    myImage.x     = _W*0.4
    myImage.y     = _H*0.90
    myImage:scale (.4, .4)

    local myImageOperator = display.newImageRect(Operator, 50,50)
    myImageOperator.x     = _W*0.5
    myImageOperator.y     = _H*0.90
    myImageOperator:scale (.5, .5)

    local myImage2 = display.newImageRect((NumImg2), 100 ,100)
    myImage2.x     = _W*0.6
    myImage2.y     = _H*0.90
    myImage2:scale (.4, .4)

end

-- Set up screen
function ScreenSetup(Event)

    -- Set up background
    bg   = display.newImage( "assets/images/bg.png", 1600, 1200);
    bg.x = _W / 6.5
    bg.y = _H / 6.5

    -- Setup numbers ( 1-9 and 0 )
    local digits = {
        { 1, 0.2, 0.2 },
        { 2, 0.5, 0.2 },
        { 3, 0.8, 0.2 },
        { 4, 0.2, 0.35 },
        { 5, 0.5, 0.35 },
        { 6, 0.8, 0.35 },
        { 7, 0.2, 0.5 },
        { 8, 0.5, 0.5 },
        { 9, 0.8, 0.5 },
        { 0, 0.5, 0.65 },
    }
    for i = 1, #digits do
        local digit = digits[ i ]
        local num   = display.newImageRect( group, "assets/images/numbers/" .. tostring( digit[ 1 ] ) .. ".png", 100 ,100)
        num.x       = _W * digit[ 2 ]
        num.y       = _H * digit[ 3 ]
        num:addEventListener( "tap", function() NumPush( digit[ 1 ] ) ; end )
    end

end

--Event Listeners For Numbers
function NumPush( value )
    CurrentInput = CurrentInput * 10 + 9
    CalcIt()
end

-- Calculates results
function CalcIt(result)

    if tostring( CurrentInput ):len() == tostring( result ):len() then
        if CurrentInput == result then
            print("You Won")
            Reset()
        else
            print("You Lost")
            Reset()
        end
    end

end

function Reset()
    group:removeSelf()
    MathSetup()
end

ScreenSetup()
MathSetup()