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HP48G_Math : English version (ou Version française)

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Author : Pierre HARDY
Date : Mars 2008
Copyright © Pierre Hardy, 2008.
E-mail author at: pierrehardy01@yahoo.be

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Math exercises on the HP-48G

Introduction

Here a small program that I wrote for my kids, weary to see their mother preparing them everyday a sheet of exercises. It allows learning the multiplication tables, the squares, the sums/subtractions up to 100, the fractions and, for the smallest, the sums up to 10. Instructions were simple: they had to have a score of 20 good answers, to them to do it as fast as possible to return to play... but this quickly became a game!

Why not on PC? The time to start up and to shut down a computer, they already finished their exercises since a long time! And a pocket calculator, you take it anywhere, in the car, in an rocking-chair, in the living room,... as a game console (games that you can easily load on it: Mine (build-in), Mastermind, Hung,... available for free on Internet).

Principles

The program has the following rules:

Sometimes it proposes the calculation (4 * 8), sometimes the result (32), you then have to provide the result, or the calculation.
It never proposes two questions in following that gives the same result (4 * 8 then 32).
There is a time limit for every question, that varies according to this one (it takes more time to type 4 * 8 that 32 as answer). If you don't reply in time, you get only a tenth of point.
You cannot "cheat"! These is to provide a response that gives the good result (after calculation), but not as expected.
For example, to 40, for a multiplication, you cannot give as answer:
- 40 : too simple, this is the question!
- 1 * 40 : this is well a multiplication, but who are we laughing at?
- 10 * 4 : this is well in the table of 4, but a little too easy!
- 10 + 30 : that gives the good result, but this is not a multiplication
- ...
But 5 * 8 and 8 * 5 are correct, just like 2 * 6 and 3 * 4 for 12.
Score is put back to zero when you jump to another module (don't try to do 20 "Plus" and present them as multiplications!), or after about 10 minutes of inactivity (in order to not get back old results).
You can choose for a single unit, or for a predefined distribution (for example: 4 multiplications, 3 sums/subtractions, 1 square and 3 conversions fraction - decimal number in average on 11 questions). When viewing score, you see which type of exercise (or which distribution) it was.

Modules

So, this program has 5 training modules:

Multiplications [MULT] : Tables of multiplications (3 to 9, tables of 1, 2 & 10 being too easy)
Squares [SQUARE] : Square calculations
Sums/Subtractions [SUM] : Sums and subtractions up to 100. The subtraction questions always give a positive response.
Fract.<- -> Dec.[F<-->D] : Fraction conversion in decimal number, and vice versa. The decimal numbers with an infinite number of decimals must be provided with exactly 5 decimals, and rounded correctly ( 1/6 = 0.16667 ).
Plus [PLUS] : Sums up to 10 (to not leave the smallest one aside, he wants also to play!)

Content

This is not the calculator manual, but how to use this program set. But for the neophytes that take the calculator in hand for the first time, I give anyway some basic commands so you can do it!

Two words of syntax: I place the commands between square brackets, but without the prefix keys (left or right shift), for example, to come back to the home directory, press [HOME] (accessible after the right shift). Commands of the first row are noted the same way, even if they are not always directly accessible (behind a menu).

First of all, go to 'Math' folder : [HOME] ([VAR]) [MATH]. This one holds the main programs, as well as the subroutines and work variables. To see them, in 'Math' directory, press [VAR] if needed, then [NXT]. By pressing the corresponding [A] ... [F] keys, you recall the content of the variable or execute the program, according to the content type.

So, here the directory content :

MATH : Main program.
- Proposes a distribution of the 5 exercises (you modify the relative weight by entering new values, and confirm with [OK], use the arrows to pass from a field to the other).
- Redefines the menu: only the programs are proposed, press [NXT] to get the second menu.
- Initializes the program (puts back the counter to zero,...)
INIT : Initialize the variables.
MULT : Tables of multiplications from 3 to 9 (the others are too easy!), in both directions.
SQUARE: Calculations of the squares from 4 to 9, in both directions.
SUM : Sums / Subtractions of numbers between 10 and 99.
[F<-->D] : Fraction conversion in decimal number and vice versa. The proposed calculations are first limited to 1/2, 1/3, 1/4, 1/5, 1/6, 1/8, 1/9, 1/10, 1/100 and 1/1000. This are the fractions you must know the numerical value of, and conversely (this is at least my very personal opinion, and 1/7 is of no use and impossible to remember!). Then, if score is good (at least 80% on at least 8 questions), I introduce the fractions multiples (5/8, 0,75, ...), except the multiples of 1/6 (too complicated).
PLUS : Sum of numbers such that he result does not exceed 10 (for my younger one, in third nursery school at that time, he too, wanted to play!).
SCORE : View the score as well as the type of question (module or distribution).
TITRE, QTITR, CFG, CST, Q, R, S, T0, TMAX, N, X : Work variables.
NB: CST is a special variable that contains the menu description: when pressing the [CST] key, the calculator looks for the variable CST in current directory , or in the path, and activates the corresponding menu.
DEBOP, FINOP, FINMULT, Nbre, RESULTAT, STR->ALG : Subroutines.

How to

From 'Math' directory, by pressing [VAR], you obtain the first screen here under (if stack is empty, [DEL] to clean it). You have then the choice between the automatic and manual option.

Manuel mode

In manual mode, you use directly the various programs, in sequence:

[VAR] : to get the programs list (and eventually [NXT] to see the following ones),
[INIT] : to re-initialize, if needed,
[SUM], [MULT], [SQUA], [F<-->D], [PLUS] : to execute the same exercise as much as required (a change of exercise re-initialize the counter!). Note that the key label cannot display "SQUARE" completely, so you only see "SQUA" to call SQUARE program
[NXT][SCORE] : to see score (don't re-initialize, can be executed at any moment) :

Those programs are also accessible through the menu [CST], and second menu ([CST]) [NXT].

NB: You can change the order in which the variables/programs appear. For more details, consult the manual, but quickly, do [Left Shift] [MEMORY] [DIR] [VARS], which puts the variables list to the level 1 of the stack. You can edit the list to change the order, without error in the names: [EDIT] then use the keys in top, the arrows, the [ALPHA] key (two times to remain in this mode) to type the letters,... When you have the programs in the good order (you don't need to list all variables or programs, they'll be let at the end automatically), press [ENTER] and [ORDER]. They're now sorted, press [VAR] to review the list.

Automatic mode

Execute [MATH], give the wished distribution in the first screen (NB: the program keeps the last configuration), and press [OK].

From there, the program puts automatically a new question as soon as you press [OK] (the program is suspended, as indicated by the small 'HALT' at the top of the screen).

To exit the program, press [END], after providing an answer (so at the end of a question).

[SCORE] Shows the score, with distribution:

[INIT] Re-initalize the counter and continue (asks the following question, according to the same distribution).

Question and Answer

For every exercise, the scenario is identical:

The program proposes a question, with the type as header:
'Sum/Subtraction', 'Multiplication', 'Square', 'Fract.<-->Dec.' or 'Plus (-> 10)',
and the menu at the screen bottom is cleared:

NB: The 'PRG' displayed at the top of the screen indicates that a program "runs" : the calculator is waiting for an entry.
You then have to key in the answer, in time, and press [ENTER].
Then the program gives:
- the question as well as the provided response,
- the result:
  - Good! : The response is correct, a point is added, small bip;
  - Too late! : Good answer, but not quickly enough, a tenth of point added;
  - Ooops! : Incorrect response, zero point;
  - Cheating! : You cheated (the provided answer is the question, ...), one point deducted!
- again the question with the correct response (at least the one generated by the program, several anwsers are sometimes possible, for example 3*4, 4*3, 2*6 or 6*2 as response to 12)
- the score: number of points / numbers of questions
Depending on the mode used, automatic or manual, press [OK] or corresponding module ([MULT],...) to get the next question.
NB: Here, the 'HALT' at the top of the screen indicates that the program is "stopped" or suspended: one can do other operations before resuming the program with 'continue' command (press [CONT]). This command is programmed on the [OK] key . This is for automatic mode only (see examples above).

With every response, a small bip is emitted, which allows (an adult?) to follow, from (not too) far the progression of the exercises. You can suppress the sound by changing the system indicator (flag) n° 56 (see manual).

Good to know

The [ON] key switch the calculator on (!), switch it [OFF] (after right shift). But this is also the [CANCEL] key, useful when the calculator is stick on a menu, or on an error. And again on same key, [CONT] continues or resume a suspended program (HALT in top status line).

When the calculator is in halt mode ('HALT' at top of screen), you can either continue the execution ([CONT]), or kill it : [PRG][NXT][RUN][KILL], command also programmed under the [END] key of menu ([CST][END]).

To change screen contrast, press and hold [ON] key, then [+] or [-].

Backup

Finally, here how to backup and restore a directory (or folder) in "port memory. I'll use here port 0, available on all models.

Backup

To copy a directory , for example 'Math' :

[HOME] to come back to main directory
'Math' [RCL] to copy the 'Math' directory at level 1 of the stack
:0:MATH [ENTER] [STO] Store the directory (on stack level 2) as "backup object" named 'MATH' in port memory 0.

Restore

Before restoring the directory previously saved, may be you'll first want to delete (purge) the existing one :
[HOME] 'Math' [Left shit][MEMORY] [DIR] [PGDIR]

Now, to restore the directory form port memory :

[Left shift][LIBRARY] [PORTS] [:0:] Display available elemtents in Port 0
[Right shift][MATH] Recall the object in the stack, here 'MATH' (by pressing the corresponding key : [A] ... [F])
'Math' [STO] [VAR] Stock the directory (at level 2) under name 'Math', and display variables (and also the directories).

For more details, consult chapiter 28 of the User's Guide.

That's it !

Just hope this will help some kids to get better in mental calculations ...

Pierre.

=*=*= Have Fun =*=*=

(1 - 11/11/2008) ¤