let loopMulTable(n) =
  let mutable s = ""
  for i=1 to n do
    s <- s + sprintf "\n"
    for x=1 to 10 do
      s <- s + sprintf "%5d" (i*x)
  s <- s + sprintf "\n"
  s;;
//version 1
let loopMulTable(n) =
  let mutable s = sprintf "%4s%4i%4i%4i%4i%4i%4i%4i%4i%4i%4i\n" ("") (11) (21) (31) (41) (51) (61) (71) (81) (91) (101)
  for i=1 to n do
    for x=1 to 10 do
      if x=1 then
        s <- s + sprintf "%4d" (ix)
      s <- s + sprintf "%4d" (ix)
    s <- s + sprintf "\n"
  s;;

//version 2
let loopMulTable(n) =
  let mutable s = ""
  let mutable first = ""
  for i=1 to n do
    for x=1 to 10 do
      if x=1 then
        s <- s + sprintf "%4d" (ix)
      elif i=1 then
        first <- sprintf "%4s%4d%4d%4d%4d%4d%4d%4d%4d%4d%4d\n" ("") (11) (21) (31) (41) (51) (61) (71) (81) (91) (101)
      s <- s + sprintf "%4d" (ix)
    s <- s + sprintf "\n"