Spotlight: Calculated Industries Gradematic 100

Spotlight: Calculated Industries Gradematic 100

Quick Facts

Model: Gradematic 100

Company: Calculated Industries

Timeline: 1983

Type: Grades conversion, Four Function

Power: 2 LR44/AR76 batteries

Number of Functions: 576 (see source)

Calculated Industries has three sequels to the Gradematic 100: Gradematic 200, Gradematic 3000, and Gradematic 4000.

Get that Grade!

The Gradematic 100 has four main modes:

* Four Function Calculator

* Timer

* Numerical Grades

* Letter Grades

Four Function Calculator (Calculate Mode)

The four function calculator is the basic calculator with the four arithmetic functions (+, -, ×, and ÷), the percent function (%), and one memory register. The [ MRC ] key acts as both a memory recall and clear. However, there is no square root or change sign key.

From any other mode, we can enter the Calculate mode by pressing the equals key [ = ].

Timer Mode

The timer has the ability to count down from a set time or count up (stopwatch).

Count Down: [ TIMER ], enter minute and seconds, then press [ TIMER ] again. The Gradematic 100 does not beep when the timer runs out.

Count Up: With the display at 0 minutes and 0 seconds, press [ TIMER ] starts the stopwatch. Press [ TIMER ] again to stop the time. The stopwatch can only be stopped once.

Numerical Grades Mode

In the Numerical Grades mode, we can enter numerical grades for students depending on the total number of assignments and tests. The general process is this:

1. Press the [ NUMERICAL GRADES ] key.

2. Enter the maximum total score, which would get the student an A+ grade, then press [ STORE*HI ].

3. Enter the minimum total score of which a student to earn a D- grade, then press [ STORE*LO ].

4. To see the break down, press the [ BREAK POINT ] key repeatedly. When ready, press the [ CONTINUE ] key.

5. For each student, enter each grade, then press the plus button [ + ]. When finished, press the [ STUDENT AVERAGE ] key get the average and the grade.

6. (Optional) Repeat step 5 to enter additional students. Press the [ MRC ] key to get the Class Average.

Example: In a class of six assignments worth 100 points each (for a total of 600 points), find a students’ average on the grades: 88, 78, 85, 92, 93, 90. The minimum grade for a D- is 60% of the maximum (360 points).

[ NUMERICAL GRADES ]

Display: E Hi Sc. 600 [ STORE*HI ]

Display: E Lo Sc. 360 [ STORE*LO]

Display: b.P. Press [ BREAK POINT ]:

360 d-

380 d

400 d+

420 C-

440 C

460 C+

480 b-

500 b

520 b+

540 A-

560 A

580 A+ (press [ BREAK POINT ] to repeat the cycle)

[ CONTINUE ] Display: Su Sd Gr

88 [ + ] 78 [ + ] 85 [ + ] 92 [ + ] 93 [ + ] 90 [ + ] Display: 6 526 (total points: 526)

[ STUDENT AVERAGE ] 6 3.26 b+

Note: For some reason, the grade below D is labeled E.

Letter Grades Mode

The Letter Grades mode operates in a similar way to the Numerical Grades Mode. The Letter Grades Mode has specialty keys [ A+ ] through [ E ]. The student average and class averages works the same way.

Example: Find a students average consisting of the grades A-, B, C+, B+, A-, A.

[ LETTER GRADES ]

Display: Ent Gr. [ A- ] [ B ] [ C+ ] [ B+ ] [ A- ] [ A ] [ STUDENT AVERAGE ]

Display: 6 3.33 b+ (average 3.33 B+)

Two Scales

The GradeMatic 100 has two GPA scales: one where A is worth 4 GPA points, and A is worth 12 GPA points. This scales can be toggled with [ A=12 ] key, which can be pressed at any time.

Final Thoughts

If you get a Gradematic 100, make sure that a manual is included. I purchased one from a local thrift mart for a $1.00 but there was no instructions. That led me to purchase another Gradematic 100 on eBay.

Another fine specialized calculator that was once made by Calculated Industries.

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.

Review: Pen + Gear SS-6613 Scientific Calculator

Review:  Pen + Gear SS-6613 Scientific Calculator

For some of us, it's already near back-to-school season.  Need a scientific calculator and on a budget?  The Pen+Gear SS-6613, which I purchased from WalMart for five bucks, may be fit. (or really, at least one to hold you over)

Quick Facts

Model: SS-6613

Company: Pen + Gear 

Production Years:  2022 - present

Power:  Battery, 1.5V

Type:  Scientific

Operating System:  Algebraic

Memory Registers:  9:  A, B, C, D, E, F, X, Y, M 

Display:  Two lines.  10-digit numbers

The display has two lines.  The top line is for equations and expressions.  The bottom line is for results.  

Features

The feature set of the Pen + Gear calculator is similar to the Casio fx-991 MS series.  You get a lot a mileage for a five dollar calculator (that isn't an app).

Complex Mode:   complex mode arithmetic with polar/rectangular conversions

Statistics:  Single data (SD) and two-variable data statistics.  Normal distribution functions (lower tail area, mid area, and upper tail area), conversion to z (labeled t) functions are included.   The six regression models available are:  linear, logarithmic, exponential, power, inverse, and quadratic.  

Equation mode:  

Unknowns:  2 or 3:  2 x 2 or 3 x 3 linear systems

Degree: 2 or 3:  roots of quadratic or cubic polynomials

Matrices:  3 matrices up to 3 rows and 3 columns.   Functions include row reduction form, transpose, inverse (by the [ X~1 ] key), and determinant.

Vectors:  3 vectors, either 2D or 3D.  Cross product (by the [ × ] key), dot product, norm (via Abs, but it's hidden)

40 scientific constants and U.S.-SI conversions.   Constants and conversions are called up by number codes, so don't lose the paper manual that comes with the calculator.  

We also get multi-expression feature, which allows us to connect calculations with a colon (:).  However, on the Pen + Gear, this is a hidden feature as the colon is not printed on the calculator.  The colon is called up by pressing [ ALPHA ] [ SDX ].

The manual to the equivalent Casio fx-991MS is presented into two manuals:

Basic Operations, Complex Numbers, Statistics, Equations:

https://support.casio.com/pdf/004/fx115MS_991MS_E.pdf

Matrices, Vectors, Integration, Derivative, Constants, Conversions:

https://support.casio.com/pdf/004/fx570MS_991MS_E.pdf

Batteries

A major difference is the battery used.   Instead of a AA battery, a coin battery (I'm thinking AR44 or LR44) but the manual states the battery is 1.5 volts.   The battery is attached to the calculator's motherboard which will need careful removal.  I am thinking that company expects the user to buy a new calculator when the battery runs out.  I would prefer a better battery compartment.  

Keyboard

Wow, the keyboard.   First, all the text is in white.  No differentiation between the shifted functions, regular functions, and alpha letters.  Also the manufacture used plain text, which does not include advance math characters and Greek characters. 

Here are the all the keyboard quirks I could find:

[ SHIFT ] (Pai):   π  

[ SHIFT ] (sqrt3):  ³√

[ X~1 ]:  x⁻¹

[ SDX ]:  ∫ dx

[ YX ]:  ^ 

[ SHIFT ] (sqrtX):  √

[ SHIFT ] (10x): 10^x

[ SHIFT ] (ex):  e^x

[ SHIFT ] (R<Q):  r∠θ

[ SHIFT ] (<):  ∠

The strangest is the Pai for pi (π).  Theta, θ, could have been substituted with ang (for angle).   I could understand the rest of it.   

Hidden:

[ ALPHA ] [ SDX ]:  colon  ( : )

[ ALPHA ] [ ) ]:  abs  (absolute value, available only in complex and vector modes)

The keyboard is the weakest point of this calculator.  

Final Thoughts

The Pen + Gear SS-6613 Scientific Calculator has a lot of features for a low-cost calculator.  Unfortunately, the lack of keyboard color and math characters are what hold me back from giving this calculator a full recommendation.  Experienced users only. 

Eddie

All original content copyright, © 2011-2023.  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. 

Review: "Little Professor" Solar

Review: "Little Professor" Solar

If you were a kid during the 1970s and 1980s, like I was, or a parent during that time, the calculator that I am about to review may bring back memories.

Quick Facts

Model:  "Little Professor" Solar (yes, the name is quoted on the calculator)

Company: Texas Instruments 

Years:  2011 - current

Type:  Education

Solar Powered 

Cost:  $ 17.50 US (Texas Instruments Educational Technology Store - 8/21/2022)

Working Our Arithmetic Muscles

The Little Professor Solar is an upgrade of the popular classic Little Professor from 1976.  Unlike the original, the solar version is 100% solar powered without a need for batteries.  

There are two modes:

*  Quiz

*  Arithmetic Tables

Quiz Mode

The Quiz Mode, activated by the [ Start ] key, selects an arithmetic problem to calculate based from one of five levels.  Level 5 is the most difficult, involving mostly two and three digit numbers.  

All the numbers are positive integers.  There is no decimal point, no negative numbers, no fractions.   All division problems divide equally without remainders.

Set the operator by pressing [ + ], [ - ], [ × ], or [ ÷ ].  The stairs button is selects the level, with the mode defaulting to level 1, which is for elementary students.  Levels 2 and higher are great for older students, those who are reviewing arithmetic, and those who want to practice their mental mathematic skills.  Change the level by pressing the key that has a stairs graphic on it (one the left side).  

On minor knock is that there is no contract between font and key on the arithmetic keys, which are bright orange.  I wish these keys would have contrast.  Thankfully, the arithmetic operators are raised so they can be felt.  

You will have two chances to solve the problem.  It is not timed, so take the time necessary.   After two incorrect answers, the Little Professor shows the correct answer.   After five problems, your score is shown.  The set is on five problems permanently.

The Quiz mode was present on the original Little Professor, but had 10 problems before displaying a score.  

Arithmetic Tables

The second mode is arithmetic drill table, which is activated by pressing the asterisk key  [ * ].  

Again, select an operator and then quickly enter a base within five seconds.  For example, if you want to practice numbers multiplied by 15, enter [ × ] 15.  

Five problems are given.

I don't believe the Arithmetic Tables mode is available on the original Little Professor.  

Final Thoughts

I think the Little Professor can be a compliment to arithmetic flash cards, possibly replace them if you don't want paper goods.  And one thing to remember is that the Little Professor Solar is not just for elementary school students, but can be used for anyone working on their arithmetic skills.  Worth a look and a buy.

There is also an app for the classic (not current) by grebulon for Android:

https://play.google.com/store/apps/details?id=com.grebulon.littleprofessor

Texas Instruments Online Store (United States, Canada, Europe):  https://epsstore.ti.com/OA_HTML/TIibeCCtdMinisites.jsp?ref_url=https%3a%2f%2feducation.ti.com%2fen%2fpurchase%2fpurchase

"Little Professor"  Wikipedia.   Last Edited on July 7, 2022 and accessed on August 21, 2022.  https://en.wikipedia.org/wiki/Little_Professor

Happy calculating,

Eddie 

All original content copyright, © 2011-2022.  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. 

Book Review: Calculus for Middle Schoolers by Serena Swegle

 Book Review: Calculus for Middle Schoolers by Serena Swegle

Just The Facts

Calculus for Middle Schoolers

Author:  Serena Swegle

Publisher:  Sunhut Publishing

Cost:  $26.50 for Paperback, $9.99 for Kindle (as of 10/23/2020)

Link:  https://www.amazon.com/Calculus-Middle-Schoolers-Serena-Swegle/dp/057871275X/ref=sr_1_3?dchild=1&keywords=Calculus+for+Middle+Schoolers&qid=1603471676&sr=8-3

Topics Covered

The number e (2.718281828...)

The common logarithm  (base 10)

The natural logarithm (base e)

Trig Functions (sine, cosine, tangent)

Sums 

Limits

Derivative - the derivative of a polynomial

Integral - the integral of a polynomial

The Derivative and Integral of e^x

An Introduction to Calculus 

The target audience is middle school students.  However, book serves as a great introduction to calculus for high school and college students who are taking calculus for the first time.  The book gives a simple, concrete introduction to various subjects, in an easy-to-read narrative.  Calculus is a complex subject, and this book allows readers, who may be intimidated about the subject, to develop a understanding.   

I would recommend this book to be read prior to the student's first calculus class.   The book can be read in one or two days, but I feel it was meant to read as one chapter a time per day or week.   

Verdict

Swegle's book is well written, in a concise language.  The chapter covers one concept at the time, which serves as a great introduction to a rich subject.   The examples are simple and apply closely to the text.   I wish Swegle put a summary of all the topics covered at the end of the book as a wrap up.  Otherwise, I recommend this book for educators and parents.   For those who have the Kindle app, $9.99 is a good price point.  Recommended.

Thank you, Serena for recommending this book for me to review.  

Eddie

All original content copyright, © 2011-2020.  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. 

TI-30 SLR+ and Memories of School

I sometimes like to visit pawn shops, because on an occasional basis, I find vintage calculators. Last weekend was a case when I found a Texas Instruments TI-30 SLR+ calculator at Arts Jewelry & Loan pawn shop in Whittier, CA. The keys, slide case, and the reference card are all kept in excellent condition!

The TI-30 SLR+ is probably the closest thing I have to the first Texas Instruments calculator, and second ever scientific calculator, I owned, the TI-30 Stat. This goes back to 1990, I think either in 7th or 8th grade. That is when I learned that "sin" stood for the sine function, not a religious transgression, and "log" had nothing to do with cutting trees.

The original TI-30 Stat was battery powered and practically never left me side. I must have read the manual hundreds of times. Unfortunately, I no longer have the TI-30 Stat, can't remember if I gave it away or it malfunctioned. For a picture of what my TI-30 looked like the datamath.net provides the picture: http://www.datamath.org/Sci/Modern/ZOOM_TI-30Stat_1992.htm

The TI-30 Stat I had turned out to be a later version, as the original version had the 2nd key marked as INV (inverse). I doubt any scientific calculator manufactured today has its modifier key marked INV.

The TI-30 SLR+ is a more advanced cousin of the TI-30 Stat. One of my high school math teacher had several of these.

TI-30 Stat vs TI-30 SLR+

According to their respective operating manuals, the TI-30 Stat stated that it had 54 functions, while the TI-30 SLR+ states that it has 63.

So far the difference between the two that I note, is that the TI-30 SLR+ has the nine following functions the TI 30 Stat didn't:

* degrees to and from degrees/minutes/seconds conversion (2 functions)
* polar coordinates to and from rectangular coordinates (2 functions)
* angle conversions: degrees to radians to gradients back to degrees (3 functions)
* statistical sums Σx and Σx^2 (2 functions)

The TI-30 SLR+ and the miniature TI-25 Stat share the same function set.

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Side note: To contrast, today, very few calculators are listed with a count of functions. I think Texas Instruments stopped counting the number of functions when the TI-85 was released in 1992.

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This calculator is going to be awesome addition to the collection. Who knew 20-plus years later I would have a collection and have a blog about math and calculators? I didn't anticipate it in 1990.



Eddie

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