11.

function IsPrimeNumber(Number)
    local X, Y
    Number = math.floor(Number)
    if (Number < 1) then return(false) end
    for X = 0, (Number - 1), 1 do
        for Y = 0, (Number - 1), 1 do
            if (X * Y == Number) then return(false) end
        end
    end
    return(true)
end
print(IsPrimeNumber(11))

12.

function GreatestCommonDivisor(VarA,VarB)
    local Greater, Smaller, I
    local Result = nil
    Greater = math.max(VarA,VarB)
    Smaller = math.min(VarA,VarB)
    for I = 1, Greater, 1 do
        if (Greater % I == 0) and (Smaller % I == 0) then
            Result = I
        end
    end
    return(Result)
end
print(GreatestCommonDivisor(441,84))

13.

function Coprime(VarA,VarB)
    local Greater, Smaller, I
    local Result = nil
    Greater = math.max(VarA,VarB)
    Smaller = math.min(VarA,VarB)
    for I = 1, Greater, 1 do
        if (Greater % I == 0) and (Smaller % I == 0) then
            Result = I
        end
    end
    if (Result == 1) then return(true) end
    return(false)
end
print(Coprime(14,15))

18.
function PrimeList(n)
    local I
    local List = {}
    local function IsPrime(Number)
        local X, Y
        Number = math.floor(Number)
        if (Number < 1) then return(false) end
        for X = 0, (Number - 1), 1 do
            for Y = 0, (Number - 1), 1 do
                if (X * Y == Number) then return(false) end
            end
        end
        return(true)
    end
    for I = 2, n, 1 do
        if IsPrime(I) then table.insert(List,I) end
    end
    return(List)
end
print(table.concat(PrimeList(10)," "))