Ted Felix

These programs have been tested on my fx-7400G, CFX-9850G, and CFX-9850GC Plus. They appear to work fine, but no warranty is provided as usual. Test them thoroughly before using them for anything serious.

The characters used on the Casio calculators aren't easy to translate into a format that works on the Web. So there is a convention that is typically used:

is the arrow key, not a hyphen and a greater-than sign.**->**

is the "implies" operator found in the PRGM | JUMP menu.**=>**

(the underscore) is the "display result command". It's the little
triangle pointing southeast that you can find in the PRGM menu.**_**

is the Square Root key.*[sqrt]*

is the "not equal" operator found in the PRGM | REL menu.*[ne]*

is the "less than or equal" operator found in the PRGM | REL menu.*[le]*

is the exponent symbol. Press the [EXP] key.**E**

is the fraction symbol which looks like a little lower right corner. Press the [a b/c] key.*[a b/c]*

Brian's page gives more detail.

Try to guess a number between 1 and 100. Press EXE twice when it says "-DISP-" to see the range, then make your guess.

1->L
100->H
Int (Ran#×100)->A
Do
L_
H_
?->G
G*[ne]*A=>"KEEP TRYING"
G>A=>G->H
G<A=>G->L
LpWhile G*[ne]*A
"GOT IT"

This program displays all the divisors of a number. Great for checking middle school math homework. Keep pressing EXE until it says DONE to see all the divisors.

?->N
For 1->D To *[sqrt]*N
If N÷D=Int (N÷D)
Then D_
N÷D_
IfEnd
Next
"DONE"

This program breaks a number down into its prime factors. Keep pressing EXE until it says DONE to see all the prime factors.

?->N
2->D
Do
If N÷D=Int (N÷D)
Then D_
N÷D->N
1->D
IfEnd
D+1->D
LpWhile D*[le][sqrt]*N
N_
"DONE"

This one computes both the greatest common divisor (better known as the greatest common factor in middle school math) and the least common multiple using Euclid's algorithm. After the GCD is displayed, press EXE to see the LCM.

?->A
?->B
A×B->P
While B*[ne]*0
B->T
A-B×Intg (A÷B)->B
T->A
WhileEnd
"GCD"
A_
"LCM"
P÷A

Note: I wasn't able to find a "modulo" operator on the Casio, so I used

`A-B×Intg (A÷B)`

I noticed that my fx-7400G will do decimal to fraction conversions if you press the [F<->D] key. However, none of the other calculators seem to do this. So, I wrote the following program to help out. It's a fairly simple program, so it has limitations.

?->N
Int N->I
Frac N->F
For 1->D To 1000
F×D->N
If Abs (Int (N+.5)-N)<1E-10×D
Then Int (N+.5)->N
Break
IfEnd
Next
I*[a b/c]*N*[a b/c]*D*[a b/c]*

This is a really slow algorithm. Try entering .001. It will take a while. I've seen other decimal to fraction programs and I need to download one to see what sort of tricks I can use to improve this. I did come up with a variation that is very fast, but it has serious limitations that render it almost useless. Basically, if you multiply the decimal by 1E10, then put 1E10 on the other side of the fraction symbol, you use the calculator's fraction feature to convert decimal to fraction for you. For example:

(.25×1E10)*[a b/c]*1E10

That Quadratic Formula sure is a pain to memorize, but it makes it really easy to program a calculator to solve quadratic equations for you. Forget about solving by factoring and completing the square. Just use this program.

"QUADRATIC"
"A"?->A
"B"?->B
"C"?->C
B^{2}-4AC->D
If D<0
Then "NO SOLUTIONS"
Stop
IfEnd
(-B+*[sqrt]*D)÷(2A)_
D>0=>(-B-*[sqrt]*D)÷(2A)_
"DONE"

Casio's download site has lots more programs including programs similar to the above for loading right into your calculator.

Casio's documentation ftp site - Go here for all the manuals.

Academic Superstore - I picked up my CFX-9850GC Plus here for a great price.

Casio Calculator Bug - Beware this bug in the Casio calculators. It places side-by-side multiplication (e.g. 3(4)) higher in precedence than the × and ÷ symbols. The workaround for this is to avoid side-by-side multiplication. Always use the × symbol even if it looks bad.

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