## Saturday, April 18, 2020

### Word Search Maker and Retro Review: Texas Instruments TI-18 SLR

Word Search Maker and Retro Review:  Texas Instruments TI-18 SLR

Word Search Maker

I was recently contacted by Phoebe and her website:  Word Search Maker.  Word Search Maker allows you to create word searches in one of four shapes:  diamond, circle, square, or spiral.  Word search maker automatically places the words in the search and also gives an answer.

Here is one I created, theme is math and calculators:  https://wordsearchwizard.com/puzzles/?id=1472

Here is a Milky Way themed word puzzle:
https://wordsearchwizard.com/puzzles/?id=1473

Create your own word searches here:  https://wordsearchwizard.com/maker/

General site:  https://wordsearchwizard.com

Setting up accounts are free.  Special thank you to Phoebe for sharing this wonderful website!

Retro Review:  Texas Instruments TI-18 SLR

Quick Facts:

Model:  TI-18 SLR
Company:  Texas Instruments
Type:  Scientific
Years:  1985-at least 1987
Display:  8 digits
Batteries:  Solar (calculator will work properly only in full light)
Original Retail Price:  Roughly \$15 - \$20
Logic:  Chain

Hybrid Between Four-Function and Scientific

The TI-18 SLR is a hybrid of a four-function calculator and a scientific calculator.

Four-Function Calculator:

*  Arithmetic (+, -, *, ÷)
*  Percent functions return the answer as soon as the percent key is pressed.
*  Operations are calculated in chain mode.  Order of operations are not followed.
*  Memory is one register:  1.   Keys regarding memory:

* M+:  calculate and add the result to memory
* M-:   calculate and subtract the result from memory
* MR:  memory recall
* MC:  memory clear

*  Square root function.  (takes the square root of the displayed number)

Scientific Calculator:

*  Square function (squares the displayed number)
*  Pi button
*  Reciprocal function (takes the reciprocal of the displayed number)
*  Parenthesis, see the next section

Parenthesis

The parenthesis key [ ( ) ] opens and closes one set of parenthesis.  There are no nested parenthesis, nor there is any indicator on the display when parenthesis are in effect.  Still, this key can aid in calculations.

Example:

Example 1:

(5^2 + 12^2) / ( 4 + 5 )

Key stroke:
[ ( ) ] 5 [ x^2] [ + ] 12 [ x^2 ] [ ( ) ]
[ ÷ ] [ ( ) ] 4 [ + ] 5 [ ( ) ]
[ = ]

Result:  18.777777

Example 2:

π * ( 18^2 - 7^2 ) + ( π * 11^2 )

Key strokes:
[ π ] [ × ] [ ( ) ] 18 [ x^2 ] [ - ] 7 [ x^2 ] [ ( ) ]
[ + ] [ ( ) ] [ π ] [ × ] 11 [ x^2 ] [ ( ) ] [ = ]

Result: 1244.0706

Note results are truncated at the last digit, not rounded.

Display

The display is one line and it's small.  Still the display is serviceable.  The left slot has three vertical indicators:  M (memory indicator) on top, - (for negative numbers) in the middle, and E (error indicator) on the bottom.

Keyboard

The keys are responsive, but I wouldn't try to speed type on the TI-18SLR.

Routine Goodies

Absolute Value:  | n |
n  [ x^2 ] [ √x ]

Sign:  sgn(n) = -1 for negative, 1 for positive (does not work for n = 0)
[MC] n [ M+ ] [ x^2 ] [ √x ] [ ÷ ] [ MR ] [ = ]

Modulus:  n mod m  with n > m, n > 0, m > 0.
[ MC ] n [ M+ ] [ 1/x ] [ × ] m [ - ] (integer part of the result) [ × ] [ MR ] [ = ]

Example:
99 mod 16 = 3
[ MC ] 16 [ M+ ] [ 1/x ] [ × ] 99   (Display: 6.1875   integer(6.1875) = 6)
[ - ] 6  [ × ] [ MR ] [ = ]

Result:  3

Verdict

A collector's item.  I wish more basic calculators included x^2, π, and 1/x, which are very useful in many calculations.

Note: This post was scheduled for Sunday, 4/19/2020, but I decided to move it up to post this 12 hours early.

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.

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