more than one formula for 1) tables and 2) calculator shell
    Pseudocode Section

        # pretty print from autoindent and ased editor
        # Convert HgA1c to Average Blood Glucose mg/dl V2
        # Console program example demo
        # written on Windows 10 on  TCL
        # working under TCL version 8.6
        # gold on TCL Club , 20aug2020
        # Each HgA1c reading usually from
        # limits of 4.0 to 11
        # has an equivalent average blood glucose
        # over a 3 month period.
        # formula from Diabetes Care, 2012.
        # Roughly 5 HgA1c converts to 100
        # mg/dl abbrev. for milligrams per deciliter
        package require Tk
        package require math::numtheory
        package require math::constants
        package require math::trig
        package require math
        namespace path {::tcl::mathop ::tcl::mathfunc math::numtheory math::trig math::constants }
        set tclprecision 17
        console show
        # following dresses up console output to easy eye
        console eval {.console config -bg palegreen}
        console eval {.console config -font {fixed 20 bold}}
        console eval {wm geometry . 40x20}
        set tclprecision 17
        #hgA1c_convert_to_average_blood_glucose mg/dl  HgA1c
        proc a1c aa {  expr { 35.6*$aa -77.3} }
        # proc precisionx used to round off floating point numbers
        proc precisionx {precision float}  {
            #  tcl:wiki:Floating-point formatting, <AM>
            # select numbers only, not used on every number.
            set x [ expr {round( 10 ** $precision * $float) / (10.0 ** $precision)} ]
            #  rounded or clipped to nearest 5ird significant figure
            set x [ format "%#.5g" $x ]
            return $x
        }
        proc summit n {
            set sum 0
            # initial hgA1c level
            set count 4.0
            puts "%| table|  printed in|TCL format |% "
            puts "%| HgA1c units | mg/dl units | comment, if any|% "
            # adapted proc from <RS>
            # printout in TCL WIKI format table
            for { set i 1 } { $i <= $n } { incr i } {
                set count [+ $count .1]
                puts "&| [ precisionx 3  $count ] | [ precisionx 3 [ a1c $count ]] | |&"
                incr sum $i
            }
            return $sum
        }
        summit 90