AOS Calculators: Duplicating a Value Without Retyping It

AOS Calculators: Duplicating a Value Without Retyping It

Note: The following applies to scientific classic calculators who operate under the algebraic operating system (AOS) (that is what Texas Instrument’s calls it). I tested this procedure with the following calculators: TI-30X ECO, HP 10bII+ (Algebraic mode), and Casio fx-260 Solar.

Introduction: Going Back to 1976

Imagine it is 1976 and you have have an SR-56 from Texas Instruments. Here is what an SR-56 looks like: http://www.datamath.org/Sci/WEDGE/ZOOM_SR-56.htm

You are tasked to calculate 1.401103287^1.401103287 and do not want to write the number twice. According to page 53 of the SR-56 manual, one approach is to key in:

1.401103287 [ y^x ] [ CE ] [ = ]

Result: 1.604057054

For that particular calculator, SR-56, pressing [ CE ] once stores the number in the display as the second operand allowing the value to duplicated without having to retype the number.

If we tried that on a modern TI-30Xa/TI-30 ECO RS, the display would clear to zero instead of showed the previous number.

However, there are a few tricks we can employ to achieve the similar result.

Trick 1: Pressing the Reciprocal Key Twice

As long as the number in the display is nonzero, pressing [ 1/x ] [ 1/x ] registers the number in the display for as a second operand. In calculators operating in AOS, executing one-argument functions only operate and effect the number in the display only.

Pressing [ 1/x ] takes the reciprocal of the number and registers the number in the display. Pressing [ 1/x ] again returns the number.

**The keystrokes omits any [ 2^nd ] or [ SHIFT ] keys.

Example 1:

Expression: x * log x

Keystrokes: x [ × ] [ 1/x ] [ 1/x ] [ LOG ] [ = ]

5.8 * log 5.8

Keystrokes: 5.8 [ × ] [ 1/x ] [ 1/x ] [ LOG ] [ = ]

Result: 4.427882363

Example 2:

Expression: x^x

Keystrokes: x [ y^x ] [ 1/x ] [ 1/x ] [ = ]

3.088 ^ 3.088

Keystrokes: 3.088 [ y^x ] [ 1/x ] [ 1/x ] [ = ]

Result: 32.51797379

Example 3:

Expression: x * sin x

Keystrokes: x [ × ] [ 1/x ] [ 1/x ] [ SIN ] [ = ]

50° * sin 50°

Keystrokes: ([DRG] to DEG/[ MODE ] (DEG))

50 [ × ] [ 1/x ] [ 1/x ] [ SIN ] [ = ]

Result: 38.30222216

4^4 + 1 / (3^3)

Keystrokes:

4 [ y^x ] [ 1/x ] [ 1/x ] [ + ]

[ ( ] 3 [ y^x ] [ 1/x ] [ 1/x ] [ ) ] [ 1/x ] [ = ]

Result: 256.037037

If the calculator has a cube function (x^3), we can execute this keystroke:

4 [ y^x ] [ 1/x ] [ 1/x ] [ + ]

[ ( ] 3 [ x^3 ] [ ) ] [ 1/x ] [ = ]

Trick 2: Inverse Function Trick

This trick extends the reciprocal trick to include a function that acts on two (and theoretically more) “reversible” functions. This trick applies to the expressions with the following format:

f(x) OP g(x)

f(x)	f^-1(x)	f(x)	f^-1(x)	f(x)	f^-1(x)
SIN	SIN^-1	e^x	LN	X^3	∛
COS	COS^-1	LN	e^x	∛	X^3
TAN	TAN^-1	10^x	LOG	Hyperbolic	Inverse Hyperbolic
SIN^-1	SIN	LOG	10^x	Inverse Hyperbolic	Hyperbolic
COS^-1	COS	X^2	√
TAN^-1	TAN	√	X^2

OP covers the arithmetic operations: [ + ], [ - ], [ × ], [ ÷ ], [ y^x ], and [ y^(1/x) ]

The general keystroke sequence is: x [ f(x) ] [ OP ] [ f^-1(x) ] [ g(x) ] [ = ]

Let’s illustrate this with a few examples. Assume the calculator is in degrees mode.

Example 1:

sin 40° * cos 40°

f(x) = sin x, f^-1(x) = sin^-1 x, g(x) = cos x

Keystrokes: 40 [ SIN ] [ × ] [ SIN^-1 ] [ COS ] [ = ]

Result: 0.492403877

Example 2:

tan 32° * sin 32°

f(x) = tan x, f^-1(x) = tan^-1 x, g(x) = sin x

Keystrokes: 32 [ TAN ] [ × ] [ TAN^-1 ] [ SIN ] [ = ]

Result: 0.331130307

Example 3:

log 881 * ln 881

f(x) = log x, f^-1(x) = 10^x, g(x) = ln x

Keystrokes: 881 [ LOG ] [ × ] [ 10^x ] [ LN ] [ = ]

Result: 19.97005314

Example 4:

e^3.5 / √3.5

f(x) = e^x, f^-1(x) = ln x, g(x) = √x

Keystrokes: 3.5 [ e^x ] [ ÷ ] [ LN ] [ √ ] [ = ]

Result: 17.70095363

Example 5:

√4.555 + e^4.555

f(x) = √x, f^-1(x) = x^2, g(x) = e^x

Keystrokes: 4.555 [ √ ] [ + ] [ x^2 ] [ e^x ] [ = ]

Result: 97.24099983

The inverse function “recovers and registers” the original x. It’s kind of simulating the LAST x feature on RPN calculators.

Sources

Datamath. “Texas Instruments SR-56“ December 5, 2001. http://www.datamath.org/Sci/WEDGE/SR-56.htm

Texas Instruments. Programmable Slid-Rule Calculator SR-56: Owner’s Manual. Dallas, TX. 1976

Eddie

All original content copyright, © 2011-2025. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

All posts are 100% generated by human effort.  The author does not use AI engines and never will.

Retro Review: Casio fx-280 FRACTION

Retro Review:  Casio fx-280 FRACTION

Quick Facts:

Model:  fx-280 FRACTION
Company:  Casio
Type:  Scientific
Years:  Introduced 1995 (mid 1990s)
Display:  10 digits
Batteries:  Solar with Battery backup, LR 44

Special thanks to Tom Manning for furnishing this calculator.  Much appreciated. 

A Bigger fx-260 Solar (II)

The Casio fx-280 FRACTION is a variation of the Casio fx-260 Solar and the fx-260 Solar II.  The modes and features are:

*  Trigonometric Functions
*  Angle Conversions:  polar, rectangular, degrees/radians/grads
*  Random Numbers
*  Logarithms and exponents
*  1 Variable Statistics
*  Fractions
*  DMS/Decimal conversions

Like the great fx-260 Solar, the fx-280 calculator is an impressive basic scientific calculator, handy for both beginners and experts.  You can check my review for the fx-260 Solar II here:  http://edspi31415.blogspot.com/2017/03/review-casio-fx-260-solar-ii-fx-82.html

Any Differences?

Yes.  The main difference is that the fx-280 has three memory registers:  A, B, and M.   Only memory M has storage addition.  Memories A, B, and M are assigned to the [ ( ], [ ) ], and [ x^y ] keys, respectively. 

The top row of keys has a [STO] (RCL)  (store/recall), pushing the [x^2] (√), [log] (10^x), and [ln] (e^x) keys to the right.  The fx-280 has no [ON] key, and the [AC] key acts as the ON key. 

The arithmetic keys, equals key, and M+/DATA key are blue instead of black.  The [ C ] and [AC] keys are red.

The fx-280 came with a quick reference card.

Thank you Tom! 

Source:

"Casio fx-280 (FRACTION)"  calculator.org  https://www.calculator.org/calculators/Casio_fx-280.html  Retrieved December 11, 2019

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

fx-260 Solar Algorithms Part II

fx-260 Solar Algorithms Part II

Decimal to Binary Conversions

This is probably best demonstrated by example. 

Algorithm:

To the decimal integer D to binary integer B:

1.  Determine the number of digits (zeroes or ones) that the binary integer is going to have.  Also, we'll store D in memory.

n = int(log D/log 2)

Each digit will represent the powers 2^(n) to 2^0.

Keystrokes: D [SHIFT] (Min) [ log ] [ ÷ ] 2 [ log ] [ = ]  // ignore the decimal part

2.  Starting with n and going to 0, calculate 2^n.  Compare 2^n to the number in memory. 

If 2^n ≤ Memory, then write a 1.  Subtract 2^n from memory:  2^n [ +/- ] [M+].  Decrease n by 1 and continue.

If 2^n > Memory, then write a 0.  Decrease n by 1 and continue.

Each digit will be written to the right of the preceding digit.

Example:  Convert 462 to binary.

Determine n:
462 [SHIFT] (Min) [ log ] [ ÷ ] 2 [ log ] [ = ]
Result:  8.851749041

Start with n = 8.  462 is stored in Memory.

In M:  462  (n = 8)
2 [ x^y ] 8 [ = ] 256,  256 ≤ 462,  [+/-] [ M+ ]   // first digit is 1
Binary:   1________

In M:  206 (n = 7)
2 [ x^y ] 7 [ = ] 128,  128 ≤ 206,  [+/-] [ M+ ]  // next digit is 1
Binary:   11_______

In M:  78 (n = 6)
2 [ x^y ] 6 [ = ] 64,  64 ≤ 78,  [+/-] [ M+ ]  // next digit is 1
Binary:   111______

In M:  14  (n = 5)
2 [ x^y ] 5 [ = ] 32,  32 > 14  // next digit is 0
Binary:   1110_____

In M:  14  (n = 4)
2 [ x^y ] 4 [ = ] 16,  16 > 14  // next digit is 0
Binary:   11100____

In M:  14  (n = 3)
2 [ x^y ] 3 [ = ] 8,  8 ≤ 14,  [+/-] [ M+ ]  // next digit is 1
Binary:   1110001___

In M:  6  (n = 2)
2 [ x^y ] 2 [ = ] 4,  4 ≤ 6,  [+/-] [ M+ ]  // next digit is 1
Binary:   11100011__

In M:  2  (n = 1)
2 [ x^y ] 1 [ = ] 2,  2 ≤ 2,  [+/-] [ M+ ]  // next digit is 1
Binary:   111000111_

In M:  2  (n = 0)
2 [ x^y ] 01 [ = ] 1,  1 > 0  // last digit is 0
Binary:   1110001110

Result:  462_10 = 1110001110_2

Combinations that Allow for Repeated Picks

Sometimes when we are choosing r objects out of a group of n objects, repeated picks are allowed.  That is, any object that is picked is put back in the pool and has a chance to be picked again.  The formula to calculate such calculations is:

nHr = (n + r - 1)! / (r! * (n - 1)!)

We can state nHr in terms of nCr (number of combinations where no repeats are allowed).

aCb = a! / (b! * (a - b)!)
Let a = n + r - 1 and b = n - 1.
Then a - b = n + r - 1 - (r - 1) = r

Then:
nHr = (n + r -1)C(n - 1)

Algorithm:
[ ( ] n [ + ] r [ - ] 1 [ ) ] [SHIFT] (nCr) [ ( ] n [ - ] 1 [ ) ] [ = ]

Example:
Find the number of combinations of picking 10 objects out of the pool of 38, where repeats are allowed.

n = 38, r = 10

[ ( ] 38 [ + ] 10 [ - ] 1 [ ) ] [SHIFT] (nCr) [ ( ] 38 [ - ] 1 [ ) ] [ = ]

Result: 5,178,066,751

Harmonic Mean of Numbers

The harmonic mean of a set of n numbers is calculated by:
HM = n / Σ(1 / x_i)

We can use the Statistics mode to calculate the harmonic mean.

Algorithm:
[ON]  // clear everything and reset calculator to COMP mode
[MODE] 0  // Mode 0 is SD mode (single data, standard deviation)
x_i [SHIFT] (1/x) [M+](DATA)
....
[SHIFT] (n) [ × ] [SHIFT] (Σx) [ = ]

Example:
Data:  3.8, 4.6, 5.9, 7.1, 7.6, 9.0  (n = 6)

[ON]
[MODE] 0 
3.8 [SHIFT] (1/x) [M+](DATA)
4.6 [SHIFT] (1/x) [M+](DATA)
5.9 [SHIFT] (1/x) [M+](DATA)
7.1 [SHIFT] (1/x) [M+](DATA)
7.6 [SHIFT] (1/x) [M+](DATA)
9.0 [SHIFT] (1/x) [M+](DATA)
[SHIFT] (n) [ × ] [SHIFT] (Σx) [ = ]

Result:  6.20145512

Atwood Machine

Given the masses of two weights (in kg) on an Atwood Machine, the following system describes the relationship between the masses, tension, and acceleration of the system:

T + M1 * a = M1 * g
T - M2 * a = M2 * g

where:
T = tension of the system (N)
a = acceleration, positive means the pulley rotates counter-clockwise; negative means the pulley rotates clockwise (m/s^2)
g = Earth's gravity constant, 9.80665 m/s^2

Assumptions:
1.  The mass of both the pulley and the string are negligent
2.  Mass 1 is on the left side of the pulley while Mass 2 is on the right. 

Solving for T and a give:
a = (M1 - M2) * g / (M1 + M2)
T = M1 * (g - a) = M2 (g + a)

Algorithm:
[ ( ] M1 [ - ] M2 [ ) ] [ × ] 9.80665 [ ÷ ] [ ( ] M1 [ + ] M2 [ ) ] [ = ]   
// acceleration is displayed

[ +/- ] [ + ] 9.80665 [ = ] [ × ] M1 [ = ]
// tension is displayed

Example:
M1 = 18 kg, M2 = 12 kg

[ ( ] 18 [ - ] 12 [ ) ] [ × ] 9.80665 [ ÷ ] [ ( ] 18 [ + ] 12 [ ) ] [ = ]   
Acceleration: 1.96133 m/s^2  (pulley is rotating counter-clockwise)

[ +/- ] [ + ] 9.80665 [ = ] [ × ] 18 [ = ]
Tension:  141.21576 N


Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

fx-260 Solar Algorithms Part I

fx-260 Solar Algorithms Part I

All results are shown to screen accuracy. 

Sphere:  Surface Area and Volume

With the radius r,
the surface area is S = 4 * π * r^2
the volume area is V = 4/3 * π * r^3

Algorithm:
r  [SHIFT] (Min) [ x² ] [ × ] [EXP](π) [ × ] 4 [ = ]    // surface area is displayed
[ × ] [ MR ] [ ÷ ] 3 [ = ]   // area is displayed

M = r

Example:
Input:
r = 3.86

Results:
3.86  [SHIFT] (Min) [ x² ] [ × ] [EXP](π) [ × ] 4 [ = ]   
Surface Area = 187.2338956

[ × ] [ MR ] [ ÷ ] 3 [ = ] 
Volume = 204.9076123

Monthly Payment of a Mortgage or Auto Loan

Input:
A = amount of the mortgage/loan
I = annual interest rate
N = number of months

The monthly payment can be found by:
PMT = ( 1 - (1 + I/1200)^-N) / (I/1200)

Algorithm:
I [ ÷ ] 1200 [ = ] [SHIFT] (Min)   // stores I/1200 into M
1 [ - ] [ ( ] 1 [ + ] [ MR ] [ ) ] [ x^y ] N [ +/- ] [ = ]
[SHIFT] (1/x) [ × ] [ MR ] [ × ] A [ = ]     // monthly payment

Example:
Input: 
I = 4  (4%)
N = 360
A = 85000

Result:
4 [ ÷ ] 1200 [ = ] [SHIFT] (Min)   // stores I/1200 into M
1 [ - ] [ ( ] 1 [ + ] [ MR ] [ ) ] [ x^y ] 360 [ +/- ] [ = ]
[SHIFT] (1/x) [ × ] [ MR ] [ × ] 85000 [ = ]     // monthly payment

PMT = 405.8030014   ($405.80)
(I/1200 = M = 3.333333333E-03)

Electromagnetic Field Strength 

Given the EIRP (effective isotropic radiated power) of a microwave (in Watts), we can calculate the following:

Power Flux Density: 
S = EIRP / (4 * π * d^2)   (W/m^2,  d = distance from the wave source in meters)

Electric Field:
E = √(30 * EIRP) /  d   (W/m)

Magnetic Field:
H = √(EIRP / (480 * π^2 * d^2) )  (A/m)

Algorithm:

Calculating Power Flux: 
EIRP [ ÷ ] [ ( ] 4 [ × ] [EXP](π) [ × ]  d [ x² ] [ ) ] [ = ]

Calculating Electric Field: 
[ ( ] EIRP [ × ] 30 [ ) ] [SHIFT] (√) [ ÷ ] 0.5 [ = ]

Calculating Magnetic Field:
[ ( ] EIRP [ ÷ ] [ ( ] 480 [ × ] [EXP](π) [ x² ] [ × ] d [ x² ] [ ) ] [ ) ] [ √ ] [ = ]

Example:
Input:
EIRP = 1800 W
d =  0.5 m   (distance)

Results:

Calculating Power Flux: 
1800 [ ÷ ] [ ( ] 4 [ × ] [EXP](π) [ × ]  0.5 [ x² ] [ ) ] [ = ]
Power Flux: 572.9577951 W/m^2

Calculating Electric Field: 
[ ( ] 1800 [ × ] 30 [ ) ] [SHIFT] (√) [ ÷ ] 0.5 [ = ]
Electric Field: 464.7580015 W/m

Calculating Magnetic Field:
[ ( ] 1800 [ ÷ ] [ ( ] 480 [ × ] [EXP](π) [ x² ] [ × ] 0.5  [ x² ] [ ) ] [ ) ] [ √ ] [ = ]
Magnetic Field: 1.232808888 A/m

Source:  Barue, Gerardo.  Microwave Engineering: Land & Space Radiocommunications John Wiley & Sons, Inc.  Hoboken, NJ  ISBN 978-0-470-08966-5 2008

Slope and Intercept with Two Points

Given two points of a line (x1, y1) and (x2, y2) we can find the slope (a) and y-intercept (b) of the general linear equation y = a*x + b.

The trick is to use the rectangular to polar conversion to find the slope:
θ = atan((y2 - y1)/(x2 -x1))
tan θ = (y2 - y1)/(x2 -x1) = slope = a

Once the slope is found, we can solve for the y-intercept:
y = a*x + b
b = y - a*x

Algorithm:
[ ( ] x1 [ - ] x2 [ ) ] [SHIFT] (R→P) [ ( ] y1 [ - ] y2 [ ) ] [ = ] [SHIFT] (X<>Y) [ tan ]
// slope is displayed

[ × ] x1* [ +/- ] [ + ] y1* [ = ]
// intercept is displayed

*x2 and y2 can be used instead

Example:
(x1, y1) = (8, 5.5)
(x2, y2) = (4, 9.5)

Result:
[ ( ] 8 [ - ] 4 [ ) ] [SHIFT] (R→P) [ ( ] 5.5 [ - ] 9.5 [ ) ] [ = ] [SHIFT] (X<>Y) [ tan ]

Slope: -1

[ × ] 8 [ +/- ] [ + ] 5.5 [ = ]

Slope: 13.5


Tomorrow will be Part II. 

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Casio Calculators and the Percent Key

Casio Calculators and the Percent Key

Introduction

The percent function on Casio calculators varies based on the calculator itself.  Let's compare six key algorithms on six Casio calculators, five current and one from the past.  We will go from the most consistent behavior to the least.

The calculators used in this study are:

SL-300VC  (four function calculator)
fx-260 Solar II  (scientific calculator - one line display)
fx-300MS 2nd Edition (scientific calculator - one line display)
fx-115ES Plus  (scientific calculator - textbook display)
fx-991EX Classwiz (scientific calculator - textbook display)
fx-115D  (scientific calculator introduced in 1991 - one line display)

Let A and B be real numbers.  In the following examples, required press of the [SHIFT] key are implied as required. 

Algorithm 1:  Multiply

Keystrokes:  A [ × ] B [ % ]

Let A = 82, B = 30

SL-300VC:  24.6 
fx-260 Solar II:  24.6
fx-300MS 2nd Edition:  24.6
fx-115ES Plus**:  123/5 ([ S<>D] 24.6) 
fx-991EX Classwiz**:  123/5  ( [ S<>D] 24.6)
fx-115D:  24.6

A [ × ] B  [ % ] calculates A * B/100.  No surprise that the results will be consistent across the board. 

**Pressing equals ( [ = ] ) is required to complete calculations involving percent calculations for the calculators with textbook display. 

Algorithm 2:  Division

Keystrokes:  A [ ÷ ] B [ % ]

Let A = 82, B = 30

SL-300VC:  273.33333 
fx-260 Solar II:  273.3333333
fx-300MS 2nd Edition:  273.3333333
fx-115ES Plus:  820/3 ([S <> D] 273.3333333) 
fx-991EX Classwiz:  820/3 ([S <> D] 273.3333333)
fx-115D: 273.3333333

A [ ÷ ] B calculates A  * 100/B.   Results are consistent across the board.

Algorithm 3:  Adding Percents

Keystrokes:  A [ × ] B [ % ] [ + ]  

A = 57, B = 11

SL-300VC: 63.27 
fx-260 Solar II: 63.27
fx-300MS 2nd Edition:  63.27
fx-115D:  63.27 

This calculates A * (1 + B/100)

If you tried the exact algorithm with the textbook style calculators like the fx-115ES Plus and the fx-991EX Classwiz, you get an error.  Use the following instead:   A [ (  ] 1 [ +  ] B [ % ] [  ) ] [ = ]

Algorithm 4:  Subtracting Percents

Keystrokes:  A [ - ] B [ % ] [ + ] 

A = 57, B = 11

SL-300VC: 50.73
fx-260 Solar II: 50.73
fx-300MS 2nd Edition:  50.73
fx-115D:  50.73 

This calculates A * (1 - B/100)

If you tried the exact algorithm with the textbook style calculators like the fx-115ES Plus and the fx-991EX Classwiz, you get an error.  Use the following keystroke algorithm instead:   A [ (  ] 1 [ -  ] B [ % ] [  ) ] [ = ]

Algorithm 5:  A - B%

Keystrokes:  A [ - ] B [ % ]

SL-300VC: 12.5 
fx-260 Solar II: 12.5
fx-300MS 2nd Edition: 12.5
fx-115ES Plus:  1784/25 ( [S<>D] 71.36) 
fx-991EX Classwiz:  1784/25 ( [S<>D] 71.36) 
fx-115D: 12.5

We see some difference on how this algorithm is calculated and it depends on the type of calculator used.

For four-function basic calculators and one-line scientific calculators, A - B% calculates the percent change:  (A - B)/B * 100

For the  textbook display calculators, the B is merely divided by 100 and subtracted from A:  A - B/100

Algorithm 6:  A + B%

Keystrokes:  A [ + ] B [ % ]

SL-300VC: 200
fx-260 Solar II: 300
fx-300MS 2nd Edition: 300
fx-115ES Plus:  201/2 ( [S<>D] 100.5) 
fx-991EX Classwiz:  201/2 ( [S<>D] 100.5) 
fx-115D: 300

This is the most inconsistent.  Quite honestly, I don't recommend this algorithm. 

What I learned:

1.  Check your manual on how to use the percent function ( % ), not matter what calculator you use. 

2.  Calculators with textbook display, the percent function ( % ) merely divides the argument by 100.

3.  This is an sample of six calculators, and as you can see, your mileage may vary. 

Have fun calculating,

Eddie

All original content copyright, © 2011-2019.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Favorite Solar Calculators – Six Years Later

Favorite Solar Calculators – Six Years Later

Favorite Solar Calculators – Reading that Blog Entry Today

On June 10, 2012, I listed some of my favorite solar calculators of all time: 

https://edspi31415.blogspot.com/2012/06/my-favorite-solar-calculators-of-all.html

I still love the TI-25X Solar, I wish the screens weren’t so damn fragile!  I went through two of them. 

I have two fx-115 ES Plus calculators, one gray and one black.  The black looks much better!

Maybe one day I’ll get the BA 35 Solar again from eBay.  Maybe I will give the Casio FC-200V a second shot. 

As of March 2018, Casio fx-3650pII is the current edition of the fx-3650P.  The fx-3650PII is in the shape of the fx-115ES/991ES/300ES/82ES Plus.  That’s about it from what I can get from research:  still four program areas with 360 steps and 7 variables.

Info on the current fx-3650PII:  http://www.casio-intl.com/asia/en/calc/products/fx-3650PII/

No, Casio still currently sells the fx-3650PII only outside the United States, which means for us Americans, we have to order online.  An open invite to Casio to stock the office stores and university stores with this model in the States is extended. 

The current Sharp EL-W516 edition, the EL-516WT, eliminated the formula storage, eliminated the catalog, and reduced the definable keys from 4 to 3, I am not happy about that.

My review on the EL-W516T:  https://edspi31415.blogspot.com/2017/07/review-sharp-el-w516t.html

Three More Inductees

I have three more to add to the list I posted in 2012:

Casio fx-991EX Classwiz – 2015 – Present

The Classwiz model is the next step in Casio solar powered calculators.  They have an icon menu, like their graphing calculators, and there is an [OPTN] key that allows users to specific mode-specific functions.  Modes includes computation (COMP), complex numbers (arithmetic, polar/rectangular conversions), base integers, matrices up to 4 x 4, vectors, statistics, distributions, basic spreadsheets up to 5 x 45, equation solving, inequalities and ratios.  The newest feature is the QR function that will take a screen shot of the calculator, or in some cases, statistical graphs, which can be retrieved from the Casio QR Website or app.

See my review of the Classwiz here:  https://edspi31415.blogspot.com/2015/11/casio-fx-991ex-classwiz-review.html

I can only hope the next iteration the Classwiz and the fx-3650P or fx-50FII merge so programming will be included.

TI-30 SLR+ – 1987 – 1990s

This is a bigger version of the TI-25X Solar (TI-30X Solar internationality).  This calculator completely runs on solar and light power.  What I look about this better than the TI-25X are the keys and the fact the display isn’t so fragile.  See my detailed blog of it here:  https://edspi31415.blogspot.com/2014/09/ti-30-slr-and-memories-of-school.html

Casio fx-260 Solar II (we can included the Casio fx-260 Solar, fx-82 Solar, fx- 82 Solar II)

Original fx-260 Solar/fx-82 Solar:  2000s – present

Current fx-260 Solar II/fx-82 Solar II: 2017 – present

I don’t know what I was thinking when I skipped this model last time.  The fx-260 offers a wide variety of functions:  trigonometry, logarithms, fractions, degrees and degrees-minute-second conversions, polar/rectangular conversions, and one variable statistics.  This is great calculator for those who want a small, compact, calculator that attacks the basics.  The fx-260 series is completely solar powered.  Pictured is the newer fx-260 Solar II, which the mode markers have been mode to the back of the calculator case.  Can’t beat the classics. 

Review:  https://edspi31415.blogspot.com/2017/03/review-casio-fx-260-solar-ii-fx-82.html

Eddie

This blog is property of Edward Shore, 2018.

Review: Casio fx-260 Solar II (fx-82 Solar II)

Review:  Casio fx-260 Solar II (fx-82 Solar II)

 Company:  Casio

Year:  2017

Type:  Scientific

Power:  Solar

Statistics: 1 Variable

Operating System:  AOS (classic)

Cost:  $8.99

So New?

Ironically, I was not able to find the fx-260 Solar II online, but saw it on a very rare trip to WalMart.  The Casio fx-260 Solar II calculator is so new that still isn’t featured on the Casio’s website (as of 3/27/2017). 

As a note:  The fx-260 is the name for the version sold in the United States.  Internationally, the calculator is known as the fx-82 Solar II, and Casio does have that calculator on its website:

https://www.casio-europe.com/euro/products/school-and-graphic-calculators/technical-scientific-calculator/fx-82solar2/

An Update of a Classic

 

fx-260 Solar original on the left, fx-260 Solar II on the right  (named fx-82 Solar (II) internationally)

The fx-260 Solar II is an update of the very classic (and still selling) Casio fx-260 Solar (outside the United States, it’s the fx-82 Solar).  Functionally, the fx-260 Solar II is the same as the classic fx-260.  As a reminder:

* Trigonometric functions

* Angle conversions: polar, rectangular, to degrees (Shift Mode 4), to radians (Shift Mode 5), and to grads (Shift Mode 6)

* Random numbers

* Logarithms and exponents

* 1 Variable Statistics

* Fractions (up to a maximum of 10 digits between the whole, numerator, and denominator parts)

* DMS/Decimal math and conversions

Pretty handy for a basic scientific calculator.  The fx-260 Solar II, like its predecessor runs entirely on solar and light power, hence a completely green calculator.  50 lux is required.

There is a NF version which was stated on the quick manual that came with the fx-260 Solar II.  The NF stands for “no fraction” and the diagram shows the fraction button [ a b/c ] button disabled.

The percent key still works the same as the predecessor.  The keystrokes:

Find N% of W:   W [ * ] N [Shift] [ = ] (%)

W is N% of the whole:   W [ ÷ ] N [Shift] [ = ] (%)

Markup/Tax:   W [ * ] N [Shift] [ = ] (%) [ + ]

Discount:  W [ * ] N [Shift] [ = ] (%) [ - ]

The differences between the fx-260 Solar II are:

 

The back of the fx-260 Solar II

1.  The processor is faster, most noticeable when try to calculator n! when  50 < n < 69.  In reality, it can be seen as negligible since the predecessor is no slow poke. 

2.  The fx-260 Solar II is has a more compact design than the original fx-260 Solar.  The fx-260 Solar II is close to a size of an iPod Touch/iPhone.  Per the manual, the dimensions of the fx-260 Solar II are 3/8” height, 2 3/4” width, and 4 3/4” depth. 

3.  The one difference I’m not a fan of is how the mode reminders are moved to the back of the calculator.  Furthermore, the reminders are white text on a white background.  It is only because of the etching that the reminders could be readable. 

Easter egg: I think this is the first time Casio dated their manual (2017). 

Final Verdict

If you are fan of small calculators, solar calculators, Casio, basic level scientific calculators, or just want something nice to add to your collection, then the fx-260 Solar II (and the original fx-260 Solar) is a nice pick up for not much money.

Eddie

This blog is property of Edward Shore, 2017.