Hi Fabrice,

As Wolfgang points out, it is indeed possible to fill-in your table with Lua: maybe you were wondering how to fill the columns 2, 3 and 4. In this case you need to use the Lua function math.mod as in the following, which is a completed version of what Wolfgang sent:

%% begin filling-with-lua.tex

\starttext

\startluacode

context.startxtable{ align = "middle,lohi", bodyfont = "9pt", framecolor = "black" }

    context.startxrow{ background = "color", backgroundcolor = "lightgray" }

        context.startxcell{ nx = 4 }

            context("Units digit of")

        context.stopxcell()

    context.stopxrow()

    context.startxrow()

        context.startxcell{ width = "1cm" }

            context.im("a")

        context.stopxcell()

        context.startxcell{ width = "1cm" }

            context.im("a^2")

        context.stopxcell()

        context.startxcell{ width = "1cm" }

            context.im("b")

        context.stopxcell()

        context.startxcell{ width = "1cm" }

            context.im("2b^2")

        context.stopxcell()

    context.stopxrow()

    for i = 0,9 do

        context.startxrow()

            for j = 1,4 do

                context.startxcell()

                    if j == 1 then

                        context(i)

                    elseif j == 2 then

                    context(math.mod(i*i,10))

 elseif j == 3 then

  context(i)

 else

  context(math.mod(2*i*i,10))

                    end

                context.stopxcell()

            end

        context.stopxrow()

    end