Hi,

Please, I am communicating the following problematic behaviour:

#------------------- problematic code ------------------------
#+begin_src calc 

sqrt(0.8)
#+end_src

#+RESULTS:
: 0.894427191 # OK

#+begin_src calc :var x=0.8
sqrt(x)
#+end_src

#+RESULTS:
=Debugger entered--Lisp error: (wrong-type-argument integer-or-marker-p 0.80000000000000004)
  math-idivmod(0.80000000000000004 0.80000000000000004)
  math-div(0.80000000000000004 0.80000000000000004)
  math-cancel-common-factor(0.80000000000000004 0.80000000000000004)
  math-simplify-sqrt()
  #[(math-simplify-expr) "\300 \207" [math-simplify-sqrt] 1]((calcFunc-sqrt 0.80000000000000004))
  math-simplify-step((calcFunc-sqrt 0.80000000000000004))
  math-simplify((calcFunc-sqrt 0.80000000000000004))
  calc-normalize-fancy((calcFunc-sqrt 0.80000000000000004))
  calc-normalize((calcFunc-sqrt 0.80000000000000004))
  math-evaluate-expr((calcFunc-sqrt 0.80000000000000004))
  #[(line) "
                  not copy-yank-able string
                                                        "
[line var-names calc-mode-map res x 0 calc-recall intern 1 "'" lookup-key nil calc-push-list calc-eval math-read-number error "Calc error \"%s\" on input \"%s\"" replace-regexp-in-string "" math-evaluate-expr mapcar org-babel-calc-maybe-resolve-var math-read-exprs] 11] ("sqrt(x)"))
  org-babel-execute:calc("sqrt(x)" ((:comments . "") (:shebang . "") (:cache . "no") (:padline . "") (:noweb . "no") (:tangle . "no") (:exports . "code") (:results . "replace") (:var x . 0.80000000000000004) (:session . "none") (:hlines . "no") (:result-type . value) (:result-params "replace") (:rowname-names) (:colname-names)))
  org-babel-execute-src-block(nil)
  org-babel-execute-src-block-maybe()
  org-babel-execute-maybe()
  org-babel-execute-safely-maybe()
  run-hook-with-args-until-success(org-babel-execute-safely-maybe)
  org-ctrl-c-ctrl-c(nil)
  call-interactively(org-ctrl-c-ctrl-c nil nil)


#---------------------- end of problematic code --------------------------------

Command line: emacs -Q -l minimal-org.el

;;; minimal-org.el:
;;; Minimal setup to load latest `org-mode'
     
;; activate debugging
(setq debug-on-error t
      debug-on-signal nil
      debug-on-quit nil)
     
;; add latest org-mode to load path
(add-to-list 'load-path (expand-file-name "~/org-mode/maint/lisp"))
(add-to-list 'load-path (expand-file-name "~/org-mode/maint/contrib/lisp" t))

;; active Babel languages
(org-babel-do-load-languages
 'org-babel-load-languages
 '((calc . t)))

;;; end of minimal-org.el

GNU Emacs 24.3.1 (i686-pc-cygwin) of 2013-08-14 on moufang

Org-mode version 8.2.4 (release_8.2.4-3-g7fe99a @ /home/usuario/org-mode/maint/lisp/)


TIA.
Miguel Ruiz.